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CVE-2021-39935

Status: AnalyzedHigh (7.5)⚠ Active exploitation

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

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

CISA KEV — actively exploited

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

AV:N sin autenticación (PR:N) permite explotación de API expuesta (CI Lint); SSRF (CWE-918) permite solicitudes no autorizadas a recursos internos; confidencialidad alta (C:H) indica lectura de datos internos.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Filter Network TrafficVulnerability ScanningSSL/TLS InspectionPrivileged Account ManagementNetwork SegmentationNetwork Intrusion Prevention

Affected technologies (1)

Gitlab — Gitlab

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2021-39935",
  "cveTags": [],
  "metrics": {
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          "role": "CISA Coordinator",
          "options": [
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              "exploitation": "active"
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              "automatable": "no"
            },
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          ],
          "version": "2.0.3",
          "timestamp": "2026-02-03T15:23:46.312568Z"
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  "published": "2021-12-13T16:15:09.367",
  "references": [
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    {
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      "value": "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"
    },
    {
      "lang": "es",
      "value": "Se ha detectado un problema en GitLab CE/EE afectando a todas las versiones a partir de 10.5 anteriores a 14.3.6, todas las versiones a partir de 14.4 anteriores a 14.4.4, todas las versiones a partir de 14.5 anteriores a 14.5.2. Los usuarios externos no autorizados podían llevar a cabo ataques de tipo Server Side Requests por medio de la API de CI Lint"
    }
  ],
  "lastModified": "2026-06-17T04:04:27.387",
  "cisaActionDue": "2026-02-24",
  "cisaExploitAdd": "2026-02-03",
  "configurations": [
    {
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  "cisaRequiredAction": "Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.",
  "cisaVulnerabilityName": "GitLab Community and Enterprise Editions Server-Side Request Forgery (SSRF) Vulnerability"
}