CVE-2021-39935

Exp

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

Published: 2021-12-13 Last update: 2026-02-04 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-39935 is rated Critical Active Threat (91.7/100): CVSS Medium severity, with high exploitation likelihood (EPSS 64.53%, 98th percentile). CISA KEV confirms active exploitation (added 2026-02-03) affecting GitLab / Community and Enterprise Editions. a weakness (CWE-918) Unauthenticated remote administrative access may be possible. EPSS rose +6.12% over the last day, indicating growing attacker interest. The CISA remediation deadline has passed—treat as an emergency patch priority.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

CISA KEV Record for CVE-2021-39935

Name: GitLab Community and Enterprise Editions Server-Side Request Forgery (SSRF) Vulnerability · CISA KEV detail

Exploit added: 2026-02-03

Action due: 2026-02-24

Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Exploit prediction scoring system (EPSS) score for CVE-2021-39935

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-21 58.41% 64.53% +6.12%
2 2026-05-06 54.60% 58.41% +3.81%
3 2026-04-27 — 54.60% —

Full EPSS history (33 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-39935

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.8 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 4.0 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-39935

OS Trackers for CVE-2021-39935

vendor priority summary link
debian not yet assigned CVE-2021-39935 not yet assigned priority: Debian including 1 source packages (gitlab), 1 status rows across 1 suites (sid): resolved 1. https://security-tracker.debian.org/tracker/CVE-2021-39935
ubuntu low CVE-2021-39935 low priority: Ubuntu including 1 source packages (gitlab), 12 status rows across 12 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, trusty, upstream, xenial): DNE 9, ignored 2, needs-triage 1. https://ubuntu.com/security/CVE-2021-39935

Affected software / configurations for CVE-2021-39935

Vendor Product Version Raw CPE
gitlab gitlab >= 10.5.0, < 14.3.6 cpe:2.3:a:gitlab:gitlab:*:*:*:*:community:*:*:*
gitlab gitlab >= 10.5.0, < 14.3.6 cpe:2.3:a:gitlab:gitlab:*:*:*:*:enterprise:*:*:*
gitlab gitlab >= 14.4.0, < 14.4.4 cpe:2.3:a:gitlab:gitlab:*:*:*:*:community:*:*:*
gitlab gitlab >= 14.4.0, < 14.4.4 cpe:2.3:a:gitlab:gitlab:*:*:*:*:enterprise:*:*:*
gitlab gitlab >= 14.5.0, < 14.5.2 cpe:2.3:a:gitlab:gitlab:*:*:*:*:community:*:*:*
gitlab gitlab >= 14.5.0, < 14.5.2 cpe:2.3:a:gitlab:gitlab:*:*:*:*:enterprise:*:*:*

References for CVE-2021-39935

cvelogic Threat Intelligence