CVE-2021-34798
published 2021-09-16CVE-2021-34798: Malformed requests may cause the server to dereference a NULL pointer. This issue affects Apache HTTP Server 2.4.48 and earlier.
PriorityP357high7.5CVSS 3.1
AVNACLPRNUINSUCNINAH
EPSS
64.51%
99.2th percentile
Malformed requests may cause the server to dereference a NULL pointer. This issue affects Apache HTTP Server 2.4.48 and earlier.
Affected
24 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| apache | http_server | <= 2.4.48 | — |
| apache_software_foundation | apache_http_server | Apache HTTP Server 2.4 – 2.4.48 | — |
| debian | apache2 | < apache2 2.4.49-1 (bookworm) | apache2 2.4.49-1 (bookworm) |
| debian | debian_linux | — | — |
| debian | debian_linux | — | — |
| debian | debian_linux | — | — |
| fedoraproject | fedora | — | — |
| fedoraproject | fedora | — | — |
| msrc | cbl2_httpd_2.4.52-1_on_cbl_mariner_2.0 | — | — |
| msrc | cm1_httpd_2.4.49-1_on_cbl_mariner_1.0 | — | — |
| oracle | communications_cloud_native_core_network_function_cloud_native_environment | — | — |
| oracle | enterprise_manager_base_platform | — | — |
| oracle | enterprise_manager_base_platform | — | — |
| oracle | http_server | — | — |
| oracle | http_server | — | — |
| oracle | instantis_enterprisetrack | — | — |
| oracle | instantis_enterprisetrack | — | — |
| oracle | instantis_enterprisetrack | — | — |
| oracle | peoplesoft_enterprise_peopletools | — | — |
| oracle | zfs_storage_appliance_kit | — | — |
| paloalto | pan-os | — | — |
| siemens | sinema_remote_connect_server | < 3.1 | 3.1 |
| siemens | sinema_server | — | — |
| tenable | tenable.sc | <= 5.19.1 | — |
Detection & IOCsextracted from sources · hover to see the quote
- →CVE-2021-34798 is triggered by malformed HTTP requests causing a NULL pointer dereference in Apache HTTP Server; detect by monitoring for unexpected httpd crashes or core dumps following malformed request patterns. ↗
- →The vulnerability is remotely exploitable with no authentication and low attack complexity (CVSS AV:N/AC:L/PR:N/UI:N), meaning any unauthenticated HTTP request to the server could be a trigger; monitor for anomalous request patterns causing server availability impact. ↗
- →In Siemens ICS environments, restrict and monitor access to Port 443/TCP as a compensating control while patching; alert on unexpected external connections to this port on affected RUGGEDCOM NMS, SINEC NMS, SINEMA Remote Connect Server, and SINEMA Server v14 devices. ↗
- ·All versions of Apache HTTP Server up to and including 2.4.48 are affected; upgrade to 2.4.49 or later to remediate CVE-2021-34798. ↗
- ·No known public exploits specifically target this vulnerability as of the CISA advisory publication date. ↗
- ·Red Hat was unable to identify a practical mitigation short of patching; no configuration-level workaround is available for the NULL pointer dereference. ↗
- ·Apache HTTP Server 2.4.49 upstream fix for CVE-2021-34798 introduced a regression in UDS URIs; ensure the regression-fix update (USN-5090-4 equivalent) is also applied. ↗
CVSS provenance
nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvdv2.05.0MEDIUMAV:N/AC:L/Au:N/C:N/I:N/A:P
osv7.5HIGH
vendor_cisco9.0CRITICAL
vendor_debian7.5HIGH
vendor_msrc7.5HIGH
vendor_oracle7.5HIGH
vendor_redhat7.5HIGH
vendor_ubuntu7.5HIGH
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GHSA
GHSA-6cg7-x9gh-4wf6: Malformed requests may cause the server to dereference a NULL pointer
ghsa_unreviewed·2022-05-24
CVE-2021-34798 [HIGH] CWE-476 GHSA-6cg7-x9gh-4wf6: Malformed requests may cause the server to dereference a NULL pointer
Malformed requests may cause the server to dereference a NULL pointer. This issue affects Apache HTTP Server 2.4.48 and earlier.
OSV
apache2 regression
osv·2021-09-28·CVSS 7.5
CVE-2021-33193 [HIGH] apache2 regression
apache2 regression
USN-5090-1 fixed vulnerabilities in Apache HTTP Server. One of the upstream
fixes introduced a regression in UDS URIs. This update fixes the problem.
Original advisory details:
James Kettle discovered that the Apache HTTP Server HTTP/2 module
incorrectly handled certain crafted methods. A remote attacker could
possibly use this issue to perform request splitting or cache poisoning
attacks. (CVE-2021-33193)
It was discovered that the Apache HTTP Server incorrectly handled certain
malformed requests. A remote attacker could possibly use this issue to
cause the server to crash, resulting in a denial of service.
(CVE-2021-34798)
Li Zhi Xin discovered that the Apache mod_proxy_uwsgi module incorrectly
handled certain request uri-paths. A remote attacker could possibly us
OSV
apache2 vulnerabilities
osv·2021-09-27·CVSS 7.5
CVE-2021-34798 [HIGH] apache2 vulnerabilities
apache2 vulnerabilities
USN-5090-1 fixed several vulnerabilities in Apache. This update provides
the corresponding update for Ubuntu 14.04 ESM and Ubuntu 16.04 ESM.
Original advisory details:
It was discovered that the Apache HTTP Server incorrectly handled certain
malformed requests. A remote attacker could possibly use this issue to
cause the server to crash, resulting in a denial of service.
(CVE-2021-34798)
It was discovered that the Apache HTTP Server incorrectly handled escaping
quotes. If the server was configured with third-party modules, a remote
attacker could use this issue to cause the server to crash, resulting in a
denial of service, or possibly execute arbitrary code. (CVE-2021-39275)
It was discovered that the Apache mod_proxy module incorrectly handled
certain request
OSV
apache2 vulnerabilities
osv·2021-09-27·CVSS 7.5
CVE-2021-33193 [HIGH] apache2 vulnerabilities
apache2 vulnerabilities
James Kettle discovered that the Apache HTTP Server HTTP/2 module
incorrectly handled certain crafted methods. A remote attacker could
possibly use this issue to perform request splitting or cache poisoning
attacks. (CVE-2021-33193)
It was discovered that the Apache HTTP Server incorrectly handled certain
malformed requests. A remote attacker could possibly use this issue to
cause the server to crash, resulting in a denial of service.
(CVE-2021-34798)
Li Zhi Xin discovered that the Apache mod_proxy_uwsgi module incorrectly
handled certain request uri-paths. A remote attacker could possibly use
this issue to cause the server to crash, resulting in a denial of service.
This issue only affected Ubuntu 20.04 LTS and Ubuntu 21.04.
(CVE-2021-36160)
It was discovered t
OSV
CVE-2021-34798: Malformed requests may cause the server to dereference a NULL pointer
osv·2021-09-16·CVSS 7.5
CVE-2021-34798 [HIGH] CVE-2021-34798: Malformed requests may cause the server to dereference a NULL pointer
Malformed requests may cause the server to dereference a NULL pointer. This issue affects Apache HTTP Server 2.4.48 and earlier.
Palo Alto
PAN-SA-2024-0012 Informational Bulletin: OSS CVEs fixed in PAN-OS
vendor_paloalto·2024-10-29·CVSS 9.8
CVE-2019-17006 [CRITICAL] PAN-SA-2024-0012 Informational Bulletin: OSS CVEs fixed in PAN-OS
PAN-SA-2024-0012 Informational Bulletin: OSS CVEs fixed in PAN-OS
The Palo Alto Networks Product Security Assurance team has evaluated the following open source software (OSS) CVEs as they relate to PAN-OS. While it was not determined that these CVEs have any significant impact on PAN-OS, they have been fixed out of an abundance of caution. CVE Summary CVE-2019-17006 This CVE is fixed in PAN-OS 10.2.0, and all later versions of PAN-OS. CVE-2021-3518 This CVE is fixed in PAN-OS 10.2.0, and all later versions of PAN-OS. CVE-2021-25219 This CVE is fixed in PAN-OS 10.2.3, and all later versions of PAN-OS. CVE-2021-27645 This CVE is fixed in PAN-OS 10.2.8, PAN-OS 11.0.2, and all later versions of PAN-OS. CVE-2021-34798 This CVE is fixed in PAN-OS 10.2.8, PAN-OS 11.0.2, and all later versions o
Oracle
Oracle Oracle Fusion Middleware Risk Matrix: SSL Module (Apache HTTP Server) — CVE-2021-34798
vendor_oracle·2023-04-15·CVSS 7.5
CVE-2021-34798 [HIGH] Oracle Oracle Fusion Middleware Risk Matrix: SSL Module (Apache HTTP Server) — CVE-2021-34798
Oracle Oracle Fusion Middleware Risk Matrix: SSL Module (Apache HTTP Server) vulnerability
CVE: CVE-2021-34798
CVSS: 7.5
Protocol: HTTP
Remote exploit: Yes
Affected versions: Network
Advisory: cpuapr2023 (APR 2023)
CISA ICS
Siemens Apache HTTP Server (Update A)
cisa_ics·2022-06-16·CVSS 7.5
[HIGH] Siemens Apache HTTP Server (Update A)
## Archived Content In an effort to keep CISA.gov current, the archive contains outdated information that may not reflect current policy or programs.
ICS Advisory
##
Siemens Apache HTTP Server (Update A)
Last RevisedOctober 13, 2022
Alert CodeICSA-22-167-06
## 1. EXECUTIVE SUMMARY
- CVSS v3 9.8
- ATTENTION: Exploitable remotely/low attack complexity
- Vendor: Siemens
- Equipment: Apache HTTP Server
- Vulnerabilities: NULL Pointer Dereference, Out-of-bounds Write, Server-side Request Forgery (SSRF)
## 2. UPDATE INFORMATION
This updated advisory is a follow-up to the advisory update titled ICSA-22-167-06 Siemens Apache HTTP Server that was published June 16, 2022, to the ICS webpage on www.cisa.gov/uscert.
## 3. RISK EVALUATION
Success
CISA ICS
Mitsubishi Electric MELSOFT iQ AppPortal
cisa_ics·2022-05-12·CVSS 5.5
[MEDIUM] Mitsubishi Electric MELSOFT iQ AppPortal
## Archived Content In an effort to keep CISA.gov current, the archive contains outdated information that may not reflect current policy or programs.
ICS Advisory
##
Mitsubishi Electric MELSOFT iQ AppPortal
Last RevisedMay 12, 2022
Alert CodeICSA-22-132-02
## 1. EXECUTIVE SUMMARY
- CVSS v3 9.8
- ATTENTION: Exploitable remotely/low attack complexity
- Vendor: Mitsubishi Electric
- Equipment: MELSOFT iQ AppPortal
- Vulnerabilities: Missing Authorization, Out-of-bounds Write, NULL Pointer Dereference, Classic Buffer Overflow, HTTP Request Smuggling, Infinite Loop
## 2. RISK EVALUATION
Successful exploitation of these vulnerabilities could result in a denial-of-service condition, malicious program execution, information disclosure, informa
Cisco
Multiple Vulnerabilities in Apache HTTP Server Affecting Cisco Products: November 2021
vendor_cisco·2021-11-24·CVSS 9.0
CVE-2021-33193 [CRITICAL] CWE-120 Multiple Vulnerabilities in Apache HTTP Server Affecting Cisco Products: November 2021
Multiple Vulnerabilities in Apache HTTP Server Affecting Cisco Products: November 2021
On September 16, 2021, the Apache Software Foundation disclosed five vulnerabilities affecting the Apache HTTP Server (httpd) 2.4.48 and earlier releases.
For a description of these vulnerabilities, see the Apache HTTP Server 2.4.49 section of the Apache HTTP Server 2.4 vulnerabilities webpage.
This advisory will be updated as additional information becomes available.
This advisory is available at the following link:https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-2.4.49-VWL69sWQ
Ubuntu
Apache HTTP Server regression
vendor_ubuntu·2021-09-28·CVSS 7.5
[HIGH] Apache HTTP Server regression
Title: Apache HTTP Server regression
Summary: USN-5090-1 introduced a regression in Apache HTTP Server.
USN-5090-1 fixed vulnerabilities in Apache HTTP Server. One of the upstream
fixes introduced a regression in UDS URIs. This update fixes the problem.
Original advisory details:
James Kettle discovered that the Apache HTTP Server HTTP/2 module
incorrectly handled certain crafted methods. A remote attacker could
possibly use this issue to perform request splitting or cache poisoning
attacks. (CVE-2021-33193)
It was discovered that the Apache HTTP Server incorrectly handled certain
malformed requests. A remote attacker could possibly use this issue to
cause the server to crash, resulting in a denial of service.
(CVE-2021-34798)
Li Zhi Xin discovered that the Apache mod_proxy_uwsgi mod
Ubuntu
Apache HTTP Server vulnerabilities
vendor_ubuntu·2021-09-27·CVSS 7.5
CVE-2021-39275 [HIGH] Apache HTTP Server vulnerabilities
Title: Apache HTTP Server vulnerabilities
Summary: Several security issues were fixed in Apache HTTP Server.
USN-5090-1 fixed several vulnerabilities in Apache. This update provides
the corresponding update for Ubuntu 14.04 ESM and Ubuntu 16.04 ESM.
Original advisory details:
It was discovered that the Apache HTTP Server incorrectly handled certain
malformed requests. A remote attacker could possibly use this issue to
cause the server to crash, resulting in a denial of service.
(CVE-2021-34798)
It was discovered that the Apache HTTP Server incorrectly handled escaping
quotes. If the server was configured with third-party modules, a remote
attacker could use this issue to cause the server to crash, resulting in a
denial of service, or possibly execute arbitrary code. (CVE-2021-39275)
Ubuntu
Apache HTTP Server vulnerabilities
vendor_ubuntu·2021-09-27·CVSS 7.5
CVE-2021-34798 [HIGH] Apache HTTP Server vulnerabilities
Title: Apache HTTP Server vulnerabilities
Summary: Several security issues were fixed in Apache HTTP Server.
James Kettle discovered that the Apache HTTP Server HTTP/2 module
incorrectly handled certain crafted methods. A remote attacker could
possibly use this issue to perform request splitting or cache poisoning
attacks. (CVE-2021-33193)
It was discovered that the Apache HTTP Server incorrectly handled certain
malformed requests. A remote attacker could possibly use this issue to
cause the server to crash, resulting in a denial of service.
(CVE-2021-34798)
Li Zhi Xin discovered that the Apache mod_proxy_uwsgi module incorrectly
handled certain request uri-paths. A remote attacker could possibly use
this issue to cause the server to crash, resulting in a denial of service.
This issue
Red Hat
httpd: NULL pointer dereference via malformed requests
vendor_redhat·2021-09-16·CVSS 7.5
CVE-2021-34798 [HIGH] CWE-476 httpd: NULL pointer dereference via malformed requests
httpd: NULL pointer dereference via malformed requests
Malformed requests may cause the server to dereference a NULL pointer. This issue affects Apache HTTP Server 2.4.48 and earlier.
A NULL pointer dereference in httpd allows an unauthenticated remote attacker to crash httpd by providing malformed HTTP requests. The highest threat from this vulnerability is to system availability.
Mitigation: Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example.
Package: httpd (Red Hat Enterprise Linux 6) - Out of support scope
Package: httpd (Red Hat Enterprise Linux 9) - Not affected
Package: httpd (Red Hat JBoss Enterprise Application Platform 6) - Out of support scope
Microsoft
NULL pointer dereference in httpd core
vendor_msrc·2021-09-14·CVSS 7.5
CVE-2021-34798 [HIGH] CWE-476 NULL pointer dereference in httpd core
NULL pointer dereference in httpd core
FAQ: Is Azure Linux the only Microsoft product that includes this open-source library and is therefore potentially affected by this vulnerability?
One of the main benefits to our customers who choose to use the Azure Linux distro is the commitment to keep it up to date with the most recent and most secure versions of the open source libraries with which the distro is composed. Microsoft is committed to transparency in this work which is why we began publishing CSAF/VEX in October 2025. See this blog post for more information. If impact to additional products is identified, we will update the CVE to reflect this.
Mariner: Mariner
apache: apache
Customer Action Required: Yes
Remediation: CBL-Mariner Releases
Reference: https://learn.microsoft.com/
Debian
CVE-2021-34798: apache2 - Malformed requests may cause the server to dereference a NULL pointer. This issu...
vendor_debian·2021·CVSS 7.5
CVE-2021-34798 [HIGH] CVE-2021-34798: apache2 - Malformed requests may cause the server to dereference a NULL pointer. This issu...
Malformed requests may cause the server to dereference a NULL pointer. This issue affects Apache HTTP Server 2.4.48 and earlier.
Scope: local
bookworm: resolved (fixed in 2.4.49-1)
bullseye: resolved (fixed in 2.4.51-1~deb11u1)
forky: resolved (fixed in 2.4.49-1)
sid: resolved (fixed in 2.4.49-1)
trixie: resolved (fixed in 2.4.49-1)
Cisco
Multiple Vulnerabilities in Apache HTTP Server Affecting Cisco Products: November 2021
vendor_cisco·CVSS 3.1
CVE-2021-34798 Multiple Vulnerabilities in Apache HTTP Server Affecting Cisco Products: November 2021
CVE-2021-34798: Multiple Vulnerabilities in Apache HTTP Server Affecting Cisco Products: November 2021
On September 16, 2021, the Apache Software Foundation disclosed five vulnerabilities affecting the Apache HTTP Server (httpd) 2.4.48 and earlier releases. For a description of these vulnerabilities, see the Apache HTTP Server 2.4.49 section of the Apache HTTP Server 2.4 vulnerabilities webpage. This advisory will be updated as additional information becomes available. This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-2.4.49-VWL69sWQ
CVSS: 3.1
CWE: CWE-120, CWE-125, CWE-476, CWE-120, CWE-125, CWE-476, CWE-918, CWE-120, CWE-125, CWE-476, CWE-120, CWE-125, CWE-476, CWE-918
Bug IDs: CSCwa33065,
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2021-34798 httpd: NULL pointer dereference via malformed requests
bugzilla·2021-09-16·CVSS 7.5
CVE-2021-34798 [HIGH] CVE-2021-34798 httpd: NULL pointer dereference via malformed requests
CVE-2021-34798 httpd: NULL pointer dereference via malformed requests
Malformed requests may cause the server to dereference a NULL pointer. This issue affects Apache HTTP Server 2.4.48 and earlier.
Reference:
http://httpd.apache.org/security/vulnerabilities_24.html
Discussion:
Created httpd tracking bugs for this issue:
Affects: fedora-all [bug 2005129]
---
This vulnerability is out of security support scope for the following product:
* Red Hat JBoss Enterprise Application Platform 6
Please refer to https://access.redhat.com/support/policy/updates/jboss_notes for more details.
---
This seems to be the related patch found by looking at the history between 2.4.48 and 2.4.49 and double-checking with the SUSE bug https://bugzilla.suse.com/show_bug.cgi?id=1190669:
https://github.com/
CTF
Jacob the Boss / Readme
ctf_writeups·CVSS 9.8
CVE-2023-38408 [CRITICAL] Jacob the Boss / Readme
# [Jacob the Boss - TryHackMe writeup](https://tryhackme.com/room/jacobtheboss)
Find a way in and learn a little more.
## Task 1
Well, the flaw that makes up this box is the reproduction found in the production environment of a customer a while ago, the verification in season consisted of two steps, the last one within the environment, we hit it head-on and more than 15 machines were vulnerable that together with the development team we were able to correct and adapt.
*First of all, add the jacobtheboss.box address to your hosts file.*
Anyway, learn a little more, have fun!
Answer the questions below
### user.txt
```
f4d491f280de360cc49e26ca1587cbcc
```
### root.txt
```
29a5641eaa0c01abe5749608c8232806
```
## Initial Enumeration
I started with a full port and service scan usi
http://httpd.apache.org/security/vulnerabilities_24.htmlhttps://cert-portal.siemens.com/productcert/pdf/ssa-685781.pdfhttps://kc.mcafee.com/corporate/index?page=content&id=SB10379https://lists.apache.org/thread.html/r3925e167d5eb1c75def3750c155d753064e1d34a143028bb32910432%40%3Cusers.httpd.apache.org%3Ehttps://lists.apache.org/thread.html/r61fdbfc26ab170f4e6492ef3bd5197c20b862ce156e9d5a54d4b899c%40%3Cusers.httpd.apache.org%3Ehttps://lists.apache.org/thread.html/r82838efc5fa6fc4c73986399c9b71573589f78b31846aff5bd9b1697%40%3Cusers.httpd.apache.org%3Ehttps://lists.apache.org/thread.html/r82c077663f9759c7df5a6656f925b3ee4f55fcd33c889ba7cd687029%40%3Cusers.httpd.apache.org%3Ehttps://lists.debian.org/debian-lts-announce/2021/10/msg00001.htmlhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNCYSR3BXT36FFF4XTCPL3HDQK4VP45R/https://security.gentoo.org/glsa/202208-20https://security.netapp.com/advisory/ntap-20211008-0004/https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-2.4.49-VWL69sWQhttps://www.debian.org/security/2021/dsa-4982https://www.oracle.com/security-alerts/cpuapr2022.htmlhttps://www.oracle.com/security-alerts/cpujan2022.htmlhttps://www.tenable.com/security/tns-2021-17http://httpd.apache.org/security/vulnerabilities_24.htmlhttps://cert-portal.siemens.com/productcert/pdf/ssa-685781.pdfhttps://kc.mcafee.com/corporate/index?page=content&id=SB10379https://lists.apache.org/thread.html/r3925e167d5eb1c75def3750c155d753064e1d34a143028bb32910432%40%3Cusers.httpd.apache.org%3Ehttps://lists.apache.org/thread.html/r61fdbfc26ab170f4e6492ef3bd5197c20b862ce156e9d5a54d4b899c%40%3Cusers.httpd.apache.org%3Ehttps://lists.apache.org/thread.html/r82838efc5fa6fc4c73986399c9b71573589f78b31846aff5bd9b1697%40%3Cusers.httpd.apache.org%3Ehttps://lists.apache.org/thread.html/r82c077663f9759c7df5a6656f925b3ee4f55fcd33c889ba7cd687029%40%3Cusers.httpd.apache.org%3Ehttps://lists.debian.org/debian-lts-announce/2021/10/msg00001.htmlhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNCYSR3BXT36FFF4XTCPL3HDQK4VP45R/https://security.gentoo.org/glsa/202208-20https://security.netapp.com/advisory/ntap-20211008-0004/https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-2.4.49-VWL69sWQhttps://www.debian.org/security/2021/dsa-4982https://www.oracle.com/security-alerts/cpuapr2022.htmlhttps://www.oracle.com/security-alerts/cpujan2022.htmlhttps://www.tenable.com/security/tns-2021-17
2021-09-16
Published