No exploitation reportedFix available

CVE-2020-36221

Q: Is CVE-2020-36221 actively exploited?

Active exploitation of CVE-2020-36221 has not been confirmed. Its EPSS score was 85.0% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2020-36221?

CVE-2020-36221 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

No exploitation reported by the sources we read.

Published2021-01-26
Fixed in10.14.6
WeaknessCWE-191

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

An integer underflow was discovered in OpenLDAP before 2.4.57 leading to slapd crashes in the Certificate Exact Assertion processing, resulting in denial of service (schema_init.c serialNumberAndIssuerCheck).

Timeline

dates in UTC

2021-01-2618:15CVE publishedNVD
2026-10-2319:23EPSS crossed 10 %FIRST EPSS

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-36221?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-36221?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Apple mac os x

Branch	Affected	Fixed in	Source
10.14	≥ 10.14.0, < 10.14.6	10.14.6	NVD
10.14	= 10.14.6	no fix published	NVD

Debian debian linux

Branch	Affected	Fixed in	Source
9.0	= 9.0	no fix published	NVD
10.0	= 10.0	no fix published	NVD

Apple macos

Branch	Affected	Fixed in	Source
11.x	≥ 11.1, < 11.4	11.4	NVD

1 more product in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Apple mac os x to 10.14.6

Advisories and patches

bugs.openldap.orgVendor Advisory
bugs.openldap.orgVendor Advisory
git.openldap.orgPatch · Vendor Advisory
git.openldap.orgPatch · Vendor Advisory
git.openldap.orgRelease Notes · Vendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.17.5read 2026-10-23
NVDCVSS 2.05read 2026-10-23
NVDweakness (CWE)CWE-191read 2026-10-23
FIRST EPSSEPSS score85.0 %read 2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: 2021-01-26
Last Modified: 2026-10-14
NVD status: Modified

Frequently asked questions

What is CVE-2020-36221?

Is CVE-2020-36221 actively exploited?

Active exploitation of CVE-2020-36221 has not been confirmed. Its EPSS score was 85.0% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-36221?

CVE-2020-36221 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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