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CVE-2020-36227

67
FAUCET Score

CVE-2020-36227 is a denial-of-service vulnerability affecting OpenLDAP versions prior to 2.4.57, including various Apple and Debian Linux distributions utilizing OpenLDAP. An unauthenticated attacker can trigger an infinite loop in the slapd daemon by sending a crafted cancel_extop Cancel operation. This flaw has a high CVSS score of 7.5 due to its network-based attack vector, low attack complexity, and high impact on availability. While its EPSS score is notably high, indicating a higher likelihood of exploitation compared to most CVEs, there is currently no evidence of active exploitation, publicly available exploit code, 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:*:*:*:*:*:*:*
>= 11.1, < 11.4CPE matchmatch criteria
cpe:2.3:o:apple:macos:*:*:*:*:*:*:*:*

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
77.74%
Probability of exploitation in next 30 days
EPSS Percentile
99.5%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.7774 is in the 99th percentile among its peer group of 51,506 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 (3)

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 (3)

mediatekllm-mediatek-5bd731d14163992dHIGH

Third-Party Package Updates in Splunk Enterprise - October 2024

Oct 14, 2024
redhatCVE-2020-36227Moderate

openldap: Infinite loop in slapd with the cancel_extop Cancel operation

Jan 26, 2021
microsoft2021-Jan/CVE-2020-36227Important

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.

Jan 12, 2021

References

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/9d0e8485f3113505743baabf1167e01e4558ccf5
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