CVE-2020-36227
published 2021-01-26CVE-2020-36227: A flaw was discovered in OpenLDAP before 2.4.57 leading to an infinite loop in slapd with the cancel_extop Cancel operation, resulting in denial of service.
PriorityP356high7.5CVSS 3.1
AVNACLPRNUINSUCNINAH
EPSS
77.74%
99.5th percentile
A flaw was discovered in OpenLDAP before 2.4.57 leading to an infinite loop in slapd with the cancel_extop Cancel operation, resulting in denial of service.
Affected
17 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| apple | macos | >= 11.1 < 11.4 | 11.4 |
| apple | macos_big_sur | — | — |
| apple | security_update_2021-003_catalina | — | — |
| apple | security_update_2021-004_mojave | — | — |
| debian | debian_linux | — | — |
| debian | debian_linux | — | — |
| debian | openldap | < openldap 2.4.57+dfsg-1 (bookworm) | openldap 2.4.57+dfsg-1 (bookworm) |
| msrc | cm1_openldap_2.4.57-2_on_cbl_mariner_1.0 | — | — |
| openldap | openldap | < 2.4.57 | 2.4.57 |
| openldap | openldap | >= 0 < 2.4.57+dfsg-1 | 2.4.57+dfsg-1 |
| openldap | openldap | >= 0 < 2.4.57+dfsg-1 | 2.4.57+dfsg-1 |
| openldap | openldap | >= 0 < 2.4.57+dfsg-1 | 2.4.57+dfsg-1 |
| openldap | openldap | >= 0 < 2.4.57+dfsg-1 | 2.4.57+dfsg-1 |
| openldap | openldap | >= 0 < 2.4.42+dfsg-2ubuntu3.12 | 2.4.42+dfsg-2ubuntu3.12 |
| openldap | openldap | >= 0 < 2.4.45+dfsg-1ubuntu1.9 | 2.4.45+dfsg-1ubuntu1.9 |
| openldap | openldap | >= 0 < 2.4.49+dfsg-2ubuntu1.6 | 2.4.49+dfsg-2ubuntu1.6 |
| openldap | openldap | >= 0 < 2.4.31-1+nmu2ubuntu8.5+esm7 | 2.4.31-1+nmu2ubuntu8.5+esm7 |
Detection & IOCsextracted from sources · hover to see the quote
- →Trigger condition: infinite loop in slapd daemon caused by the cancel_extop Cancel operation — monitor for slapd process consuming 100% CPU or becoming unresponsive after receiving a Cancel extended operation ↗
- →Process to monitor: slapd — an infinite loop in this process is the direct observable symptom of exploitation ↗
- ·Red Hat Enterprise Linux 8 and 9 are NOT affected because the slapd server is not shipped in those packages — do not prioritize patching openldap on RHEL 8/9 for this CVE ↗
- ·Only deployments running the slapd server component of OpenLDAP are vulnerable; client-only OpenLDAP installations are not exposed ↗
- ·Debian-based systems are fixed in openldap version 2.4.57+dfsg-1 across all active releases (bookworm, bullseye, forky, sid, trixie) ↗
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_debian7.5HIGH
vendor_msrc7.5HIGH
vendor_redhat7.5HIGH
vendor_ubuntu7.5HIGH
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Ubuntu
OpenLDAP vulnerabilities
vendor_ubuntu·2025-08-17·CVSS 7.5
CVE-2020-36221 [HIGH] OpenLDAP vulnerabilities
Title: OpenLDAP vulnerabilities
Summary: Several security issues were fixed in OpenLDAP.
It was discovered that OpenLDAP incorrectly handled Certificate Exact
Assertion processing. A remote attacker could possibly use this issue to
cause OpenLDAP to crash, resulting in a denial of service. (CVE-2020-36221)
It was discovered that OpenLDAP incorrectly handled saslAuthzTo processing.
A remote attacker could use this issue to cause OpenLDAP to crash,
resulting in a denial of service, or possibly execute arbitrary code.
(CVE-2020-36222, CVE-2020-36224, CVE-2020-36225, CVE-2020-36226)
It was discovered that OpenLDAP incorrectly handled Return Filter control
handling. A remote attacker could use this issue to cause OpenLDAP to
crash, resulting in a denial of service, or possibly execute arbit
CISA ICS
Siemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP V3.1
cisa_ics·2023-12-14
Siemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP V3.1
ICS Advisory
##
Siemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP V3.1
Release DateDecember 14, 2023
Alert CodeICSA-23-348-10
As of January 10, 2023, CISA will no longer be updating ICS security advisories for Siemens product vulnerabilities beyond the initial advisory. For the most up-to-date information on vulnerabilities in this advisory, please see Siemens' ProductCERT Security Advisories (CERT Services | Services | Siemens Global).
View CSAF
## 1. EXECUTIVE SUMMARY
- CVSS v3 9.8
- ATTENTION: Exploitable remotely/low attack complexity
- Vendor: Siemens
- Equipment: SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP V3.1
- Vulnerabilities: Improper Restriction of XML External Entity Reference, Time-of-check Time-of-use (TOCTOU) Race Condition, Command Injection, Miss
Apple
CVE-2020-36227: Security Update 2021-003 Catalina
vendor_apple·2021-05-24·CVSS 7.5
CVE-2020-36227 [HIGH] CVE-2020-36227: Security Update 2021-003 Catalina
Apple Security Update: About the security content of Security Update 2021-003 Catalina
Product: Security Update 2021-003 Catalina
CVE: CVE-2020-36227
Component: CVE-2020-36227
Apple
CVE-2020-36227: macOS Big Sur 11.4
vendor_apple·2021-05-24·CVSS 7.5
CVE-2020-36227 [HIGH] CVE-2020-36227: macOS Big Sur 11.4
Apple Security Update: About the security content of macOS Big Sur 11.4
Product: macOS Big Sur
Version: 11.4
CVE: CVE-2020-36227
Component: CVE-2020-36227
Apple
CVE-2020-36227: Security Update 2021-004 Mojave
vendor_apple·2021-05-24·CVSS 7.5
CVE-2020-36227 [HIGH] CVE-2020-36227: Security Update 2021-004 Mojave
Apple Security Update: About the security content of Security Update 2021-004 Mojave
Product: Security Update 2021-004 Mojave
CVE: CVE-2020-36227
Component: CVE-2020-36227
Ubuntu
OpenLDAP vulnerabilities
vendor_ubuntu·2021-02-08·CVSS 7.5
CVE-2020-36223 [HIGH] OpenLDAP vulnerabilities
Title: OpenLDAP vulnerabilities
Summary: Several security issues were fixed in OpenLDAP.
It was discovered that OpenLDAP incorrectly handled Certificate Exact
Assertion processing. A remote attacker could possibly use this issue to
cause OpenLDAP to crash, resulting in a denial of service. (CVE-2020-36221)
It was discovered that OpenLDAP incorrectly handled saslAuthzTo processing.
A remote attacker could use this issue to cause OpenLDAP to crash,
resulting in a denial of service, or possibly execute arbitrary code.
(CVE-2020-36222, CVE-2020-36224, CVE-2020-36225, CVE-2020-36226)
It was discovered that OpenLDAP incorrectly handled Return Filter control
handling. A remote attacker could use this issue to cause OpenLDAP to
crash, resulting in a denial of service, or possibly execute arbit
Red Hat
openldap: Infinite loop in slapd with the cancel_extop Cancel operation
vendor_redhat·2021-01-26·CVSS 7.5
CVE-2020-36227 [HIGH] CWE-835 openldap: Infinite loop in slapd with the cancel_extop Cancel operation
openldap: Infinite loop in slapd with the cancel_extop Cancel operation
A flaw was discovered in OpenLDAP before 2.4.57 leading to an infinite loop in slapd with the cancel_extop Cancel operation, resulting in denial of service.
Statement: This flaw does not affect openldap as shipped with Red Hat Enterprise Linux 8 because the slapd server is not shipped. While Red Hat Enterprise Linux 7 does ship the slapd server, this flaw is out of support scope for Red Hat Enterprise Linux 7 and earlier. For more information on support scope, see https://access.redhat.com/support/policy/updates/errata/ .
Package: compat-openldap (Red Hat Enterprise Linux 6) - Out of support scope
Package: openldap (Red Hat Enterprise Linux 6) - Out of support scope
Package: compat-openldap (Red Hat Enterprise Lin
Microsoft
A flaw was discovered in OpenLDAP before 2.4.57 leading to an infinite loop in slapd with the cancel_extop Cancel operation resulting in denial of service.
vendor_msrc·2021-01-12·CVSS 7.5
CVE-2020-36227 [HIGH] CWE-835 A flaw was discovered in OpenLDAP before 2.4.57 leading to an infinite loop in slapd with the cancel_extop Cancel operation resulting in denial of service.
A flaw was discovered in OpenLDAP before 2.4.57 leading to an infinite loop in slapd with the cancel_extop Cancel operation resulting in denial of service.
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
mitr
Debian
CVE-2020-36227: openldap - A flaw was discovered in OpenLDAP before 2.4.57 leading to an infinite loop in s...
vendor_debian·2020·CVSS 7.5
CVE-2020-36227 [HIGH] CVE-2020-36227: openldap - A flaw was discovered in OpenLDAP before 2.4.57 leading to an infinite loop in s...
A flaw was discovered in OpenLDAP before 2.4.57 leading to an infinite loop in slapd with the cancel_extop Cancel operation, resulting in denial of service.
Scope: local
bookworm: resolved (fixed in 2.4.57+dfsg-1)
bullseye: resolved (fixed in 2.4.57+dfsg-1)
forky: resolved (fixed in 2.4.57+dfsg-1)
sid: resolved (fixed in 2.4.57+dfsg-1)
trixie: resolved (fixed in 2.4.57+dfsg-1)
OSV
openldap vulnerabilities
osv·2025-08-17·CVSS 7.5
CVE-2020-36221 [HIGH] openldap vulnerabilities
openldap vulnerabilities
It was discovered that OpenLDAP incorrectly handled Certificate Exact
Assertion processing. A remote attacker could possibly use this issue to
cause OpenLDAP to crash, resulting in a denial of service. (CVE-2020-36221)
It was discovered that OpenLDAP incorrectly handled saslAuthzTo processing.
A remote attacker could use this issue to cause OpenLDAP to crash,
resulting in a denial of service, or possibly execute arbitrary code.
(CVE-2020-36222, CVE-2020-36224, CVE-2020-36225, CVE-2020-36226)
It was discovered that OpenLDAP incorrectly handled Return Filter control
handling. A remote attacker could use this issue to cause OpenLDAP to
crash, resulting in a denial of service, or possibly execute arbitrary
code. (CVE-2020-36223)
It was discovered that OpenLDAP inco
GHSA
GHSA-6w5v-vmwv-xcwj: A flaw was discovered in OpenLDAP before 2
ghsa_unreviewed·2022-05-24
CVE-2020-36227 [HIGH] CWE-835 GHSA-6w5v-vmwv-xcwj: A flaw was discovered in OpenLDAP before 2
A flaw was discovered in OpenLDAP before 2.4.57 leading to an infinite loop in slapd with the cancel_extop Cancel operation, resulting in denial of service.
OSV
openldap vulnerabilities
osv·2021-02-08·CVSS 7.5
CVE-2020-36221 [HIGH] openldap vulnerabilities
openldap vulnerabilities
It was discovered that OpenLDAP incorrectly handled Certificate Exact
Assertion processing. A remote attacker could possibly use this issue to
cause OpenLDAP to crash, resulting in a denial of service. (CVE-2020-36221)
It was discovered that OpenLDAP incorrectly handled saslAuthzTo processing.
A remote attacker could use this issue to cause OpenLDAP to crash,
resulting in a denial of service, or possibly execute arbitrary code.
(CVE-2020-36222, CVE-2020-36224, CVE-2020-36225, CVE-2020-36226)
It was discovered that OpenLDAP incorrectly handled Return Filter control
handling. A remote attacker could use this issue to cause OpenLDAP to
crash, resulting in a denial of service, or possibly execute arbitrary
code. (CVE-2020-36223)
It was discovered that OpenLDAP inco
OSV
CVE-2020-36227: A flaw was discovered in OpenLDAP before 2
osv·2021-01-26·CVSS 7.5
CVE-2020-36227 [HIGH] CVE-2020-36227: A flaw was discovered in OpenLDAP before 2
A flaw was discovered in OpenLDAP before 2.4.57 leading to an infinite loop in slapd with the cancel_extop Cancel operation, resulting in denial of service.
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
http://seclists.org/fulldisclosure/2021/May/64http://seclists.org/fulldisclosure/2021/May/65http://seclists.org/fulldisclosure/2021/May/70https://bugs.openldap.org/show_bug.cgi?id=9428https://git.openldap.org/openldap/openldap/-/commit/9d0e8485f3113505743baabf1167e01e4558ccf5https://git.openldap.org/openldap/openldap/-/tags/OPENLDAP_REL_ENG_2_4_57https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3Ehttps://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3Ehttps://lists.debian.org/debian-lts-announce/2021/02/msg00005.htmlhttps://security.netapp.com/advisory/ntap-20210226-0002/https://support.apple.com/kb/HT212529https://support.apple.com/kb/HT212530https://support.apple.com/kb/HT212531https://www.debian.org/security/2021/dsa-4845http://seclists.org/fulldisclosure/2021/May/64http://seclists.org/fulldisclosure/2021/May/65http://seclists.org/fulldisclosure/2021/May/70https://bugs.openldap.org/show_bug.cgi?id=9428https://git.openldap.org/openldap/openldap/-/commit/9d0e8485f3113505743baabf1167e01e4558ccf5https://git.openldap.org/openldap/openldap/-/tags/OPENLDAP_REL_ENG_2_4_57https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3Ehttps://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3Ehttps://lists.debian.org/debian-lts-announce/2021/02/msg00005.htmlhttps://security.netapp.com/advisory/ntap-20210226-0002/https://support.apple.com/kb/HT212529https://support.apple.com/kb/HT212530https://support.apple.com/kb/HT212531https://www.debian.org/security/2021/dsa-4845
2021-01-26
Published