What is CVE-2020-36227?

CVE-2020-36227 is a high-severity vulnerability in Apple macOS, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 7.5/10. Published 2021-01-26.

How severe is CVE-2020-36227?

High severity. CVSS v3 base score is 7.5 out of 10.

Is CVE-2020-36227 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Apple macOS

CVE-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.

Published 2021-01-26 · last modified 2026-10-14.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.772 (99.6th percentile), scored 2026-10-17.

High probability of exploitation in the next 30 days — patch promptly. 100th percentile — 99.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.777 · newest: 0.772 · change: -0.005

Affected products

Apple macOS
Openldap
Debian Linux — versions 9.0, 10.0

Weakness classification (CWE)

CWE-835 — Loop with Unreachable Exit Condition (Infinite Loop)

Public proof-of-concept exploits

References

git.openldap.org/openldap/openldap/-/tags/OPENLDAP_REL_ENG_2_4_57 (Release Notes, Vendor Advisory)
bugs.openldap.org/show_bug.cgi (Issue Tracking, Vendor Advisory)
git.openldap.org/openldap/openldap/-/commit/9d0e8485f3113505743baabf1167e01e455… (Patch, Vendor Advisory)
lists.debian.org/debian-lts-announce/2021/02/msg00005.html (mailing-list, Mailing List, Third Party Advisory)
www.debian.org/security/2021/dsa-4845 (vendor-advisory, Third Party Advisory)
security.netapp.com/advisory/ntap-20210226-0002/ (Third Party Advisory)
support.apple.com/kb/HT212529 (Third Party Advisory)
support.apple.com/kb/HT212531 (Third Party Advisory)
support.apple.com/kb/HT212530 (Third Party Advisory)
seclists.org/fulldisclosure/2021/May/70 (mailing-list, Mailing List, Third Party Advisory)

Frequently asked questions

What is CVE-2020-36227?: CVE-2020-36227 is a high-severity vulnerability in Apple macOS, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 7.5/10. Published 2021-01-26.
How severe is CVE-2020-36227?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2020-36227 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.