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CVE-2020-36221

70
FAUCET Score

CVE-2020-36221 is an integer underflow vulnerability in OpenLDAP versions prior to 2.4.57, also affecting Apple and Debian, which can lead to a denial of service (DoS) due to slapd crashes during Certificate Exact Assertion processing. With a CVSS score of 7.5 (High), this vulnerability is remotely exploitable with low attack complexity, requiring no user interaction, and its primary impact is availability. Despite its high risk score and EPSS percentile, there is currently no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
< 2.4.57CPE matchmatch criteria
cpe:2.3:a:openldap:openldap:*:*:*:*:*:*:*:*
9.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
10.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
>= 10.14.0, < 10.14.6CPE matchmatch criteria
cpe:2.3:o:apple:mac_os_x:*:*:*:*:*:*:*:*
10.14.6CPE matchmatch criteria
cpe:2.3:o:apple:mac_os_x:10.14.6:-:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
84.22%
Probability of exploitation in next 30 days
EPSS Percentile
99.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.8422 is in the 100th percentile among its peer group of 51,485 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (4)

githubpatch availablevia llm_extracted
View patch
mediatekpatch availablevia llm_extracted
Fixed in: 9.3.1, 9.2.3, 9.1.6
microsoftpatch availablevia msrc
Product: 16831-16820Fixed in: 2.4.57-2
microsoftpatch availablevia msrc
Product: cm1 openldap 2.4.57-2 on CBL Mariner 1.0Fixed in: 2.4.57-2

Vendor Advisories (4)

mediatekllm-mediatek-5bd731d14163992dHIGH

Third-Party Package Updates in Splunk Enterprise - October 2024

Oct 14, 2024
githubllm-github-1c7760a29ebd6810HIGH

AS-2022-012: OpenLDAP

Aug 29, 2022
redhatCVE-2020-36221Moderate

openldap: Integer underflow in serialNumberAndIssuerCheck in schema_init.c

Jan 26, 2021
microsoft2021-Jan/CVE-2020-36221Important

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).

Jan 12, 2021

References

bugs.openldap.org / show_bug.cgi
Issue TrackingVendor Advisory
bugs.openldap.org / show_bug.cgi
Issue TrackingVendor Advisory
seclists.org / fulldisclosure/2021/May/64
Mailing ListThird Party Advisory
seclists.org / fulldisclosure/2021/May/65
Mailing ListThird Party Advisory
seclists.org / fulldisclosure/2021/May/70
Mailing ListThird Party Advisory
git.openldap.org / openldap/openldap/-/commit/38ac838e4150c626bbfa0082b7e2cf3a2bb4df31
PatchVendor Advisory
git.openldap.org / openldap/openldap/-/commit/58c1748e81c843c5b6e61648d2a4d1d82b47e842
PatchVendor Advisory
git.openldap.org / openldap/openldap/-/tags/OPENLDAP_REL_ENG_2_4_57
Release NotesVendor Advisory
lists.apache.org / thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E
lists.apache.org / thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E
lists.debian.org / debian-lts-announce/2021/02/msg00005.html
Mailing ListThird Party Advisory
security.netapp.com / advisory/ntap-20210226-0002
Third Party Advisory
support.apple.com / kb/HT212529
Third Party Advisory
support.apple.com / kb/HT212530
Third Party Advisory
support.apple.com / kb/HT212531
Third Party Advisory
debian.org / security/2021/dsa-4845
Third Party Advisory