CVE-2021-39935

MEDIUMCISA KEVEPSS 98th pctl

6.8

CVSS v3

Description

An issue has been discovered in GitLab CE/EE affecting all versions starting from 10.5 before 14.3.6, all versions starting from 14.4 before 14.4.4, all versions starting from 14.5 before 14.5.2. Unauthorized external users could perform Server Side Requests via the CI Lint API

CWE-918Server-Side Request Forgery (SSRF)

How to fix

Remediation Available

gitlabDebian

Fixed in:15.10.8+ds1-2CVE-2021-39935

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityHigh

Privileges RequiredNone

User InteractionNone

ScopeChanged

Impact

ConfidentialityHigh

IntegrityNone

AvailabilityNone

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

Exploit Intelligence

35.65%probability of exploitation in 30 days

98thpercentile

Very high risk: more likely to be exploited than 98% of all known CVEs.

Known Exploited Vulnerability (CISA KEV)

Remediation due: 2026-02-24

References

Vendor Advisory1

gitlab.com

Third-Party Advisory2

Government Resource1

cisa.gov

Related Vulnerabilities

Other CWE-918 (Server-Side Request Forgery (SSRF)) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-21893	High	8.2	100%	KEV + Ransom	-
CVE-2021-40438	Critical	9.0	100%	KEV + Ransom	Fix
CVE-2021-34473	Critical	9.1	100%	KEV + Ransom	Fix
CVE-2021-26855	Critical	9.1	100%	KEV + Ransom	Fix
CVE-2021-21985	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2022-41040	High	8.8	100%	KEV + Ransom	Fix

Common questions

How do I fix CVE-2021-39935?

Upgrade gitlab on debian unstable to 15.10.8+ds1-2 or later.

Is CVE-2021-39935 being actively exploited?

Yes. CVE-2021-39935 is listed in the CISA Known Exploited Vulnerabilities catalog, which means exploitation has been observed in the wild. US federal agencies were required to remediate it by 2026-02-24. Treat it as a priority whatever its CVSS score says.

How severe is CVE-2021-39935?

CVE-2021-39935 has a CVSS v3 base score of 6.8, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2021-39935 affect?

Published advisories record a fix for gitlab (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-02-04.