Threat Intelligence / CVE / CVE-2021-39935

CVE-2021-39935 — Gitlab

CISA KEV

CVSS v3.1 6.8 (MEDIUM) · EPSS 41.4% (higher than 97.4% of all scored CVEs) · Priority 9/10 · Published 2021-12-13

As of 2026-02-04, CVE-2021-39935 is a MEDIUM-severity vulnerability in Gitlab, CVSS v3.1 6.8, EPSS 41.4% (97.4th percentile). It is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-02-03), with a US federal remediation deadline of 2026-02-24. Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2021-39935, most recently “GitLab CI Lint API SSRF — CVE-2021-39935 Patch Bypass, CISA KEV Feb 2026, Cloud Metadata Theft, Internal Service Enumeration, 4-Year Exploitation Gap on Self-Managed Instances”.

Last updated: 2026-02-04

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

The record classifies CVE-2021-39935 under weakness class CWE-918. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality. 2 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 1735 days ago.

Severity and exploitation probability

CVSS v3.1 base score: 6.8 — MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N
EPSS (FIRST): 41.4% probability of exploitation in the next 30 days, higher than 97.4% of all scored CVEs
CISA KEV: Listed since 2026-02-03, federal remediation deadline 2026-02-24
Threadlinqs priority: 9/10 — CISA KEV-listed, which Threadlinqs floors at 9
Published: 2021-12-13, last modified 2026-02-04

Is CVE-2021-39935 being exploited?

CISA added CVE-2021-39935 to the Known Exploited Vulnerabilities catalog on 2026-02-03, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2026-02-24 under BOD 22-01. It currently carries a trending score of 39 in the Threadlinqs vulnerability feed.

Affected products and versions

Gitlab: Gitlab

Showing 1 of 2 recorded product entries.

How to fix CVE-2021-39935

Vendor advisory: https://gitlab.com/gitlab-org/gitlab/-/issues/346187. Because CVE-2021-39935 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2026-02-24. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

Threat activity tracking CVE-2021-39935

1 tracked threat in the Threadlinqs corpus references CVE-2021-39935, either in the campaign’s CVE list or as an indicator on the campaign record.

GitLab CI Lint API SSRF — CVE-2021-39935 Patch Bypass, CISA KEV Feb 2026, Cloud Metadata Theft, Internal Service Enumeration, 4-Year Exploitation Gap on Self-Managed Instances — HIGH · 2026-02-03

Sources

Seeded from nvd and not yet processed by the Threadlinqs enrichment pipeline, so blank CVSS, EPSS or KEV fields above mean NOT MEASURED rather than measured-absent.

Full detection coverage & IOCs for threats exploiting CVE-2021-39935 are available via the Threadlinqs MCP server (Purple tier). View plans →

← all vulnerabilities · Markdown version · Threadlinqs Intelligence