How severe is CVE-2021-39935?

CVE-2021-39935 has a CVSS 3.x base score of 6.8, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-39935 being actively exploited?

Yes. CVE-2021-39935 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2026-02-03, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2021-39935?

CVE-2021-39935 primarily affects Gitlab. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-39935?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2021-39935 have an EU (EUVD) identifier?

Yes. CVE-2021-39935 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-26291. It is also flagged as exploited in the EUVD (since 2026-02-03).

When was CVE-2021-39935 published?

CVE-2021-39935 was published on 2021-12-13 and last updated on 2026-06-17.

CVE-2021-39935

CVE-2021-39935 is a medium-severity vulnerability in Gitlab with a CVSS 3.x base score of 6.8. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2026-02-03). The underlying weakness is classified as CWE-918.

Key facts

Severity: Medium (CVSS 3.x base score 6.8)
CVSS v2: 5.0
EPSS exploit prediction: 36% (98th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2026-02-03)
EU (EUVD) id: EUVD-2021-26291
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2026-02-03)
Weakness: CWE-918
Affected product: Gitlab
Published: 2021-12-13
Last modified: 2026-06-17

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

Frequently asked questions

What is CVE-2021-39935?: 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
How severe is CVE-2021-39935?: CVE-2021-39935 has a CVSS 3.x base score of 6.8, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-39935 being actively exploited?: Yes. CVE-2021-39935 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2026-02-03, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2021-39935?: CVE-2021-39935 primarily affects Gitlab. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-39935?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2021-39935 have an EU (EUVD) identifier?: Yes. CVE-2021-39935 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-26291. It is also flagged as exploited in the EUVD (since 2026-02-03).
When was CVE-2021-39935 published?: CVE-2021-39935 was published on 2021-12-13 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:gitlab:gitlab:*:*:*:*:community:*:*:*
cpe:2.3:a:gitlab:gitlab:*:*:*:*:enterprise:*:*:*

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