CVE-2020-36227

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 77.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-01-26 · updated 2026-10-14
Weakness: CWE-835

Description

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 products

Apple macOS: from 11.1 before 11.4 — fixed in 11.4
Debian Linux: 9.0, 10.0
openldap: before 2.4.57 — fixed in 2.4.57

How to fix

Upgrade to a fixed version: Apple macOS 11.4; openldap 2.4.57. Check the vendor advisory for mitigations.

References

http://seclists.org/fulldisclosure/2021/May/64
http://seclists.org/fulldisclosure/2021/May/65
http://seclists.org/fulldisclosure/2021/May/70
https://bugs.openldap.org/show_bug.cgi?id=9428
https://git.openldap.org/openldap/openldap/-/commit/9d0e8485f3113505743baabf1167e01e4558ccf5
https://git.openldap.org/openldap/openldap/-/tags/OPENLDAP_REL_ENG_2_4_57
https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E
https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E
https://lists.debian.org/debian-lts-announce/2021/02/msg00005.html
https://security.netapp.com/advisory/ntap-20210226-0002/
https://support.apple.com/kb/HT212529
https://support.apple.com/kb/HT212530

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