CVE-2020-36221: apple mac_os_x Integer Underflow (Wrap or Wraparound)

CVSS: 7.5v3.1HighModified

AliasesALPINE-CVE-2020-36221UBUNTU-CVE-2020-36221DEBIAN-CVE-2020-36221

Published 25-01-2021Last modified 14-10-2026

Vulnerability summary

CVE-2020-36221 is a high (CVSS 7.5) Integer Underflow (Wrap or Wraparound) vulnerability in apple mac_os_x. EPSS estimates a 84.99% chance of exploitation in the next 30 days, higher than 99.7% of scored vulnerabilities.

Overall risk

47/100

0100

Medium · default modelHow is this calculated?

CVSS score

7.5/10

010

High · v3.1 (NVD)

EPSS score

84.99%

0%100%

Critical · +0.77 pp in 30 days

KEVNot listedIn no KEV catalog

RansomwareNone recordedNo known use recorded

Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 10 · Related 7

DLA-2544-1 DSA-4845-1 MGASA-2021-0105 OPENSUSE-SU-2021:0408-1 SUSE-SU-2021:0692-1 SUSE-SU-2021:0693-1+4 more

Timeline

25-01-2021
PublishedVulnerability first disclosed.
14-10-2026
Last modifiedVulnerability information updated.

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).

CVSS metrics

5 scores · 4 sources · 2 versions

v3.17.5v2.05.0

EPSS trend

Probability

84.99%

Chance of exploitation in the next 30 days

Percentile

100%

Versus all other CVEs

30-day change

+0.77 pp

From 84.22% on 19-09-2026

19-09-202619-10-2026

EPSS score

84.99%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

CWE-191Integer Underflow (Wrap or Wraparound)The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.

Affected systems

Apple2 products

mac_os_x≥ 10.14.0, < 10.14.6 | 10.14.6 | 10.14.6:security_update_2019-004 | 10.14.6:security_update_2019-005 | 10.14.6:security_update_2019-006 | 10.14.6:security_update_2019-007 | 10.14.6:security_update_2020-001 | 10.14.6:security_update_2020-002 | 10.14.6:security_update_2020-003 | 10.14.6:security_update_2020-004 | 10.14.6:security_update_2020-005 | 10.14.6:security_update_2020-006 | 10.14.6:security_update_2020-007 | 10.14.6:security_update_2021-001 | 10.14.6:security_update_2021-002 | 10.14.6:security_update_2021-003 | 10.14.6:supplemental_update | 10.14.6:supplemental_update_2
macos≥ 11.1, < 11.4

Debian2 products