Known exploited vulnerability
CVE-2021-39935
The short answer
CVE-2021-39935 affects GitLab GitLab and is rated high (CVSS 7.5). CISA added it to the Known Exploited Vulnerabilities catalog on 2026-02-03: attackers are using it, so patch it first.
What it is
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
Weakness: CWE-918.
Severity
7.5 high
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Exploited (CISA KEV)
Yes, since Feb 3, 2026
Federal due date Feb 24, 2026
EPSS, next 30 days
36%
Higher than 98% of scored CVEs
How it can be exploited
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- None
- Availability impact
- None
What CISA says to do
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Affected products
GitLab. NVD's record lists the exact affected versions.
References
- gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-39935.json Third Party Advisory
- gitlab.com/gitlab-org/gitlab/-/issues/346187 Issue TrackingVendor Advisory
- hackerone.com/reports/1236965 Permissions RequiredThird Party Advisory
- gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-39935.json Third Party Advisory
- gitlab.com/gitlab-org/gitlab/-/issues/346187 Issue TrackingVendor Advisory
- hackerone.com/reports/1236965 Permissions RequiredThird Party Advisory
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-39935 US Government Resource
Questions
Is CVE-2021-39935 being exploited?
Yes. CISA added CVE-2021-39935 to its Known Exploited Vulnerabilities catalog on 2026-02-03, with a federal remediation due date of 2026-02-24.
How do I fix CVE-2021-39935?
CISA's 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.
From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.
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