CVE-2021-28169
published 2021-06-09CVE-2021-28169: For Eclipse Jetty versions <= 9.4.40, <= 10.0.2, <= 11.0.2, it is possible for requests to the ConcatServlet with a doubly encoded path to access protected…
PriorityP278medium5.3CVSS 3.1
AVNACLPRNUINSUCLINAN
ITWEXPLOITVulnCheck KEV
Exploited in the wild
EPSS
78.48%
99.5th percentile
For Eclipse Jetty versions <= 9.4.40, <= 10.0.2, <= 11.0.2, it is possible for requests to the ConcatServlet with a doubly encoded path to access protected resources within the WEB-INF directory. For example a request to `/concat?/%2557EB-INF/web.xml` can retrieve the web.xml file. This can reveal sensitive information regarding the implementation of a web application.
Affected
9 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | debian_linux | — | — |
| debian | debian_linux | — | — |
| debian | jetty9 | < jetty9 9.4.39-2 (bookworm) | jetty9 9.4.39-2 (bookworm) |
| eclipse | jetty | < 9.4.41 | 9.4.41 |
| eclipse | jetty | >= 10.0.0 < 10.0.3 | 10.0.3 |
| eclipse | jetty | >= 11.0.0 < 11.0.3 | 11.0.3 |
| oracle | communications_cloud_native_core_policy | — | — |
| oracle | rest_data_services | < 21.3 | 21.3 |
| the_eclipse_foundation | eclipse_jetty | unspecified – 9.4.40 | — |
Detection & IOCsextracted from sources · hover to see the quote
- →Look for HTTP GET requests to /concat or /static endpoints containing doubly encoded path traversal sequences (e.g., %2557EB-INF) targeting WEB-INF resources such as web.xml. ↗
- →The double-encoding technique uses %2557 to represent 'W' (i.e., %25 decodes to %, then %57 decodes to W), bypassing WEB-INF path protection in ConcatServlet. ↗
- ·Vulnerability only affects deployments where ConcatServlet or WelcomeFilter components of Jetty are explicitly deployed; applications not using these servlets are not affected. ↗
- ·Affected versions are Jetty <= 9.4.40, <= 10.0.2, and <= 11.0.2; detections should be scoped to these version ranges. ↗
CVSS provenance
nvdv3.15.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
nvdv2.05.0MEDIUMAV:N/AC:L/Au:N/C:P/I:N/A:N
osv5.3MEDIUM
vulncheck5.3MEDIUM
vendor_debian5.3MEDIUM
vendor_oracle5.3MEDIUM
vendor_redhat5.3MEDIUM
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Oracle
Oracle Oracle Communications Risk Matrix: Policy (Eclipse Jetty) — CVE-2021-28169
vendor_oracle·2022-04-15·CVSS 5.3
CVE-2021-28169 [MEDIUM] Oracle Oracle Communications Risk Matrix: Policy (Eclipse Jetty) — CVE-2021-28169
Oracle Oracle Communications Risk Matrix: Policy (Eclipse Jetty) vulnerability
CVE: CVE-2021-28169
CVSS: 5.3
Protocol: HTTP
Remote exploit: Yes
Affected versions: Network
Advisory: cpuapr2022 (APR 2022)
Red Hat
jetty: requests to the ConcatServlet and WelcomeFilter are able to access protected resources within the WEB-INF directory
vendor_redhat·2021-06-08·CVSS 5.3
CVE-2021-28169 [MEDIUM] CWE-200 jetty: requests to the ConcatServlet and WelcomeFilter are able to access protected resources within the WEB-INF directory
jetty: requests to the ConcatServlet and WelcomeFilter are able to access protected resources within the WEB-INF directory
For Eclipse Jetty versions <= 9.4.40, <= 10.0.2, <= 11.0.2, it is possible for requests to the ConcatServlet with a doubly encoded path to access protected resources within the WEB-INF directory. For example a request to `/concat?/%2557EB-INF/web.xml` can retrieve the web.xml file. This can reveal sensitive information regarding the implementation of a web application.
Statement: In OpenShift Container Platform (OCP), the hive/presto/hadoop components that comprise the OCP metering stack, ship the vulnerable version of jetty.
Since the release of OCP 4.6, the metering product has been deprecated [1], hence the affected components are marked as wontfix.
This may be fi
Debian
CVE-2021-28169: jetty9 - For Eclipse Jetty versions <= 9.4.40, <= 10.0.2, <= 11.0.2, it is possible for r...
vendor_debian·2021·CVSS 5.3
CVE-2021-28169 [MEDIUM] CVE-2021-28169: jetty9 - For Eclipse Jetty versions <= 9.4.40, <= 10.0.2, <= 11.0.2, it is possible for r...
For Eclipse Jetty versions <= 9.4.40, <= 10.0.2, <= 11.0.2, it is possible for requests to the ConcatServlet with a doubly encoded path to access protected resources within the WEB-INF directory. For example a request to `/concat?/%2557EB-INF/web.xml` can retrieve the web.xml file. This can reveal sensitive information regarding the implementation of a web application.
Scope: local
bookworm: resolved (fixed in 9.4.39-2)
bullseye: resolved (fixed in 9.4.39-2)
forky: resolved (fixed in 9.4.39-2)
sid: resolved (fixed in 9.4.39-2)
trixie: resolved (fixed in 9.4.39-2)
OSV
Jetty Utility Servlets ConcatServlet Double Decoding Information Disclosure Vulnerability
osv·2021-06-10
CVE-2021-28169 [MEDIUM] Jetty Utility Servlets ConcatServlet Double Decoding Information Disclosure Vulnerability
Jetty Utility Servlets ConcatServlet Double Decoding Information Disclosure Vulnerability
Requests to the `ConcatServlet` and `WelcomeFilter` are able to access protected resources within the `WEB-INF` directory. For example a request to the `ConcatServlet` with a URI of `/concat?/%2557EB-INF/web.xml` can retrieve the web.xml file. This can reveal sensitive information regarding the implementation of a web application.
This occurs because both `ConcatServlet` and `WelcomeFilter` decode the supplied path to verify it is not within the `WEB-INF` or `META-INF` directories. It then uses this decoded path to call `RequestDispatcher` which will also do decoding of the path. This double decoding allows paths with a doubly encoded `WEB-INF` to bypass this security check.
### Impact
This affects
GHSA
Jetty Utility Servlets ConcatServlet Double Decoding Information Disclosure Vulnerability
ghsa·2021-06-10
CVE-2021-28169 [MEDIUM] CWE-200 Jetty Utility Servlets ConcatServlet Double Decoding Information Disclosure Vulnerability
Jetty Utility Servlets ConcatServlet Double Decoding Information Disclosure Vulnerability
Requests to the `ConcatServlet` and `WelcomeFilter` are able to access protected resources within the `WEB-INF` directory. For example a request to the `ConcatServlet` with a URI of `/concat?/%2557EB-INF/web.xml` can retrieve the web.xml file. This can reveal sensitive information regarding the implementation of a web application.
This occurs because both `ConcatServlet` and `WelcomeFilter` decode the supplied path to verify it is not within the `WEB-INF` or `META-INF` directories. It then uses this decoded path to call `RequestDispatcher` which will also do decoding of the path. This double decoding allows paths with a doubly encoded `WEB-INF` to bypass this security check.
### Impact
This affects
OSV
CVE-2021-28169: For Eclipse Jetty versions <= 9
osv·2021-06-09·CVSS 5.3
CVE-2021-28169 [MEDIUM] CVE-2021-28169: For Eclipse Jetty versions <= 9
For Eclipse Jetty versions <= 9.4.40, <= 10.0.2, <= 11.0.2, it is possible for requests to the ConcatServlet with a doubly encoded path to access protected resources within the WEB-INF directory. For example a request to `/concat?/%2557EB-INF/web.xml` can retrieve the web.xml file. This can reveal sensitive information regarding the implementation of a web application.
VulnCheck
Eclipse Jetty ConcatServlet Vulnerability
vulncheck·2021·CVSS 5.3
CVE-2021-28169 [MEDIUM] Eclipse Jetty ConcatServlet Vulnerability
Eclipse Jetty ConcatServlet Vulnerability
For Eclipse Jetty versions <= 9.4.40, <= 10.0.2, <= 11.0.2, it is possible for requests to the ConcatServlet with a doubly encoded path to access protected resources within the WEB-INF directory. For example a request to `/concat?/%2557EB-INF/web.xml` can retrieve the web.xml file. This can reveal sensitive information regarding the implementation of a web application.
Affected: eclipse jetty
Required Action: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.
Exploitation References: https://unit42.paloaltonetworks.com/recent-exploits-network-security-trends/; https://app.crowdsec.net/cti/cve-explorer/CVE-2021-28169
No detection rules found.
Nuclei
Eclipse Jetty ConcatServlet - Information Disclosure
nuclei·CVSS 5.3
CVE-2021-28169 [MEDIUM] Eclipse Jetty ConcatServlet - Information Disclosure
Eclipse Jetty ConcatServlet - Information Disclosure
Eclipse Jetty through 9.4.40, through 10.0.2, and through 11.0.2 is susceptible to information disclosure. Requests to the ConcatServlet with a doubly encoded path can access protected resources within the WEB-INF directory, thus enabling an attacker to potentially obtain sensitive information, modify data, and/or execute unauthorized administrative operations in the context of the affected site.
Template:
id: CVE-2021-28169
info:
name: Eclipse Jetty ConcatServlet - Information Disclosure
author: pikpikcu
severity: medium
description: |
Eclipse Jetty through 9.4.40, through 10.0.2, and through 11.0.2 is susceptible to information disclosure. Requests to the ConcatServlet with a doubly encoded path can access protected resources withi
Unit42
Network Security Trends: Recent Exploits Observed in the Wild Include Remote Code Execution, Cross-Site Scripting and More
blogs_unit42·2022-08-19·CVSS 8.8
CVE-2021-20166 [HIGH] Network Security Trends: Recent Exploits Observed in the Wild Include Remote Code Execution, Cross-Site Scripting and More
Threat Research Center
Trend Reports
Vulnerabilities
## Network Security Trends: Recent Exploits Observed in the Wild Include Remote Code Execution, Cross-Site Scripting and More
Yue Guan
Published: August 19, 2022
Trend Reports
Vulnerabilities
Attack analysis
CVE-2021-20166
CVE-2021-20167
CVE-2021-21881
CVE-2021-24762
CVE-2021-28169
CVE-2021-31589
CVE-2021-39226
CVE-2021-4045
CVE-2021-43711
CVE-2022-21371
CVE-2022-21662
CVE-2022-22536
CVE-2022-22947
CVE-2022-22954
CVE-2022-22963
CVE-2022-22965
CVE-2022-24112
CVE-2022-24260
CVE-2022-25060
CVE-2022-25075
CVE-2022-25134
CVE-2022-27226
CVE-2022-29464
Exploit in the wild
Network security trends
## Executive Summary
Recent observations of exploits used in the wild reveal that attackers have been making use
Unit42
Network Security Trends: Recent Exploits Observed in the Wild Include Remote Code Execution, Cross-Site Scripting and More
blogs_unit42·2022-08-19
Network Security Trends: Recent Exploits Observed in the Wild Include Remote Code Execution, Cross-Site Scripting and More
## Executive Summary
Recent observations of exploits used in the wild reveal that attackers have been making use of newly published remote code execution vulnerabilities in VMware ONE Access and Identity Manager and Spring Cloud Function, Spring MVC and Spring Web Flux, among others. Attackers have also been taking advantage of a cross-site scripting vulnerability in WordPress core, and SQL injection vulnerabilities in VoIPmonitor GUI and other services. In our observations of network security trends, Unit 42 researchers select exploits of the latest published attacks that defenders should know based on the availability of proofs of concept (PoCs), the severity of the vulnerabilities the exploits are based on and the ease of exploitation.
Other insights that could assist defenders includ
Greynoiseio
NoiseLetter August 2025
blogs_greynoiseio
NoiseLetter August 2025
CVE Disclosure Early Warning Get an early warning when traffic spikes indicate a high likelihood of new disclosures
Compromised Asset Detection Find out immediately if an asset communicates with a malicious IP address
Vulnerability Prioritization Get real-time insight into active exploitation trends to better understand risk and severity
SOC Efficiency Filter out noisy, low priority and false-positive alerts from mass internet scanners
Incident Investigation Add context to incidents to speed the determinations of scope and timelines
Threat Hunting Quickly identify anomalous behavior and enrich your threat hunting campaigns
Why GreyNoise
CVE Disclosure Early Warning Get an early warning when traffic spikes indicate a high likelihood of new disclosures
Compromised Asset Detection Fin
Bugzilla
CVE-2021-28169 jetty: requests to the ConcatServlet and WelcomeFilter are able to access protected resources within the WEB-INF directory
bugzilla·2021-06-11·CVSS 5.3
CVE-2021-28169 [MEDIUM] CVE-2021-28169 jetty: requests to the ConcatServlet and WelcomeFilter are able to access protected resources within the WEB-INF directory
CVE-2021-28169 jetty: requests to the ConcatServlet and WelcomeFilter are able to access protected resources within the WEB-INF directory
For Eclipse Jetty versions <= 9.4.40, <= 10.0.2, <= 11.0.2, it is possible for requests to the ConcatServlet with a doubly encoded path to access protected resources within the WEB-INF directory. For example a request to `/concat?/%2557EB-INF/web.xml` can retrieve the web.xml file. This can reveal sensitive information regarding the implementation of a web application.
Reference:
https://github.com/eclipse/jetty.project/security/advisories/GHSA-gwcr-j4wh-j3cq
Discussion:
Created jetty tracking bugs for this issue:
Affects: fedora-all [bug 1971017]
---
This vulnerability is out of security support scope for the following products:
* Red Hat JBoss
arXiv
Security Review of Ethereum Beacon Clients
arxiv_fulltext·2021-09-23
Security Review of Ethereum Beacon Clients
center
[width=7cm]beacon
empty
1cm
Security Review of Ethereum Beacon Clients
1cm
JP Aumasson -- Taurus, Switzerland -- [email protected],
Denis Kolegov -- Tomsk State University, Russia -- [email protected]
Evangelia Stathopoulou -- University College London, UK -- [email protected]
0.5cm
Version
0.5cm
Supported by the Ethereum Foundation.
center
## Abstract
The beacon chain is the backbone of the Ethereum's evolution
towards a proof-of-stake-based scalable network.
Beacon clients are the applications implementing the services
required to operate the beacon chain, namely validators, beacon
nodes, and slashers.
Security defects in beacon clients could lead to loss of funds,
consensus rules violation, network congestion, and other
inconveniences.
We repo
https://github.com/eclipse/jetty.project/security/advisories/GHSA-gwcr-j4wh-j3cqhttps://lists.apache.org/thread.html/r04a4b4553a23aff26f42635a6ae388c3b162aab30a88d12e59d05168%40%3Cjira.kafka.apache.org%3Ehttps://lists.apache.org/thread.html/r234f6452297065636356f43654cdacef565b8f9ceb0e0c07ffb8c73b%40%3Cdev.kafka.apache.org%3Ehttps://lists.apache.org/thread.html/r2721aba31a8562639c4b937150897e24f78f747cdbda8641c0f659fe%40%3Cusers.kafka.apache.org%3Ehttps://lists.apache.org/thread.html/r284de9c5399486dfff12ab9e7323ca720dd7019a9a3e11c8510a7140%40%3Cjira.kafka.apache.org%3Ehttps://lists.apache.org/thread.html/r29678972c3f8164b151fd7a5802785d402e530c09870a82ffc7681a4%40%3Cdev.kafka.apache.org%3Ehttps://lists.apache.org/thread.html/r32b0b640ad2be3b858f0af51c68a7d5c5a66a462c8bbb93699825cd3%40%3Cissues.zookeeper.apache.org%3Ehttps://lists.apache.org/thread.html/r33eb06b05afbc7df28d31055cae0cb3fd36cab808c884bf6d680bea5%40%3Cdev.zookeeper.apache.org%3Ehttps://lists.apache.org/thread.html/r67c4f90658fde875521c949448c54c98517beecdc7f618f902c620ec%40%3Cissues.zookeeper.apache.org%3Ehttps://lists.apache.org/thread.html/r8a1a332899a1f92c8118b0895b144b27a78e3f25b9d58a34dd5eb084%40%3Cnotifications.zookeeper.apache.org%3Ehttps://lists.apache.org/thread.html/r91e34ff61aff8fd25a3f2a21539597c6ef7589a31c199b0a9546477c%40%3Cjira.kafka.apache.org%3Ehttps://lists.apache.org/thread.html/rb1292d30462b9baedea7c5d9594fc75990d9aa0ec223b48054ca9c25%40%3Cjira.kafka.apache.org%3Ehttps://lists.apache.org/thread.html/rbefa055282d52d6b58d29a79fbb0be65ab0a38d25f00bd29eaf5e6fd%40%3Cnotifications.zookeeper.apache.org%3Ehttps://lists.apache.org/thread.html/rd5b52362f5edf98e0dcab6541a381f571cccc05ad9188e793af688f3%40%3Cjira.kafka.apache.org%3Ehttps://lists.apache.org/thread.html/rddbb4f8d5db23265bb63d14ef4b3723b438abc1589f877db11d35450%40%3Cissues.zookeeper.apache.org%3Ehttps://lists.apache.org/thread.html/ref1c161a1621504e673f9197b49e6efe5a33ce3f0e6d8f1f804fc695%40%3Cjira.kafka.apache.org%3Ehttps://lists.apache.org/thread.html/rf36f1114e84a3379b20587063686148e2d5a39abc0b8a66ff2a9087a%40%3Cissues.zookeeper.apache.org%3Ehttps://lists.apache.org/thread.html/rfff6ff8ffb31e8a32619c79774def44b6ffbb037c128c5ad3eab7171%40%3Cissues.zookeeper.apache.org%3Ehttps://lists.debian.org/debian-lts-announce/2021/06/msg00017.htmlhttps://security.netapp.com/advisory/ntap-20210727-0009/https://www.debian.org/security/2021/dsa-4949https://www.oracle.com/security-alerts/cpuapr2022.htmlhttps://www.oracle.com/security-alerts/cpujan2022.htmlhttps://www.oracle.com/security-alerts/cpuoct2021.htmlhttps://github.com/eclipse/jetty.project/security/advisories/GHSA-gwcr-j4wh-j3cqhttps://lists.apache.org/thread.html/r04a4b4553a23aff26f42635a6ae388c3b162aab30a88d12e59d05168%40%3Cjira.kafka.apache.org%3Ehttps://lists.apache.org/thread.html/r234f6452297065636356f43654cdacef565b8f9ceb0e0c07ffb8c73b%40%3Cdev.kafka.apache.org%3Ehttps://lists.apache.org/thread.html/r2721aba31a8562639c4b937150897e24f78f747cdbda8641c0f659fe%40%3Cusers.kafka.apache.org%3Ehttps://lists.apache.org/thread.html/r284de9c5399486dfff12ab9e7323ca720dd7019a9a3e11c8510a7140%40%3Cjira.kafka.apache.org%3Ehttps://lists.apache.org/thread.html/r29678972c3f8164b151fd7a5802785d402e530c09870a82ffc7681a4%40%3Cdev.kafka.apache.org%3Ehttps://lists.apache.org/thread.html/r32b0b640ad2be3b858f0af51c68a7d5c5a66a462c8bbb93699825cd3%40%3Cissues.zookeeper.apache.org%3Ehttps://lists.apache.org/thread.html/r33eb06b05afbc7df28d31055cae0cb3fd36cab808c884bf6d680bea5%40%3Cdev.zookeeper.apache.org%3Ehttps://lists.apache.org/thread.html/r67c4f90658fde875521c949448c54c98517beecdc7f618f902c620ec%40%3Cissues.zookeeper.apache.org%3Ehttps://lists.apache.org/thread.html/r8a1a332899a1f92c8118b0895b144b27a78e3f25b9d58a34dd5eb084%40%3Cnotifications.zookeeper.apache.org%3Ehttps://lists.apache.org/thread.html/r91e34ff61aff8fd25a3f2a21539597c6ef7589a31c199b0a9546477c%40%3Cjira.kafka.apache.org%3Ehttps://lists.apache.org/thread.html/rb1292d30462b9baedea7c5d9594fc75990d9aa0ec223b48054ca9c25%40%3Cjira.kafka.apache.org%3Ehttps://lists.apache.org/thread.html/rbefa055282d52d6b58d29a79fbb0be65ab0a38d25f00bd29eaf5e6fd%40%3Cnotifications.zookeeper.apache.org%3Ehttps://lists.apache.org/thread.html/rd5b52362f5edf98e0dcab6541a381f571cccc05ad9188e793af688f3%40%3Cjira.kafka.apache.org%3Ehttps://lists.apache.org/thread.html/rddbb4f8d5db23265bb63d14ef4b3723b438abc1589f877db11d35450%40%3Cissues.zookeeper.apache.org%3Ehttps://lists.apache.org/thread.html/ref1c161a1621504e673f9197b49e6efe5a33ce3f0e6d8f1f804fc695%40%3Cjira.kafka.apache.org%3Ehttps://lists.apache.org/thread.html/rf36f1114e84a3379b20587063686148e2d5a39abc0b8a66ff2a9087a%40%3Cissues.zookeeper.apache.org%3Ehttps://lists.apache.org/thread.html/rfff6ff8ffb31e8a32619c79774def44b6ffbb037c128c5ad3eab7171%40%3Cissues.zookeeper.apache.org%3Ehttps://lists.debian.org/debian-lts-announce/2021/06/msg00017.htmlhttps://security.netapp.com/advisory/ntap-20210727-0009/https://www.debian.org/security/2021/dsa-4949https://www.oracle.com/security-alerts/cpuapr2022.htmlhttps://www.oracle.com/security-alerts/cpujan2022.htmlhttps://www.oracle.com/security-alerts/cpuoct2021.html
2021-06-09
Published
Exploited in the wild