CVE-2021-39867Network attack vector

SSRF via Gitea Importer DNS rebinding

Published Oct 5, 2021 · Updated Aug 4, 2024

Server-side request forgery in affected GitLab CE/EE releases allows remote authenticated users to reach internal services through Gitea imports. The importer relies on reverse DNS when validating a supplied Gitea host, allowing a later rebound DNS answer to direct the outbound request to a different address. A low-privileged account able to start a Gitea import and control the supplied host's DNS is required; resulting requests can act on resources reachable from the GitLab server.

CVSS severity6.5
Medium
EPSS probability0.89%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Server-side request forgery in affected GitLab CE/EE releases allows remote authenticated users to reach internal services through Gitea imports. The importer relies on reverse DNS when validating a supplied Gitea host, allowing a later rebound DNS answer to direct the outbound request to a different address. A low-privileged account able to start a Gitea import and control the supplied host's DNS is required; resulting requests can act on resources reachable from the GitLab server.

The record

CVE
CVE-2021-39867
Published
Oct 5, 2021
Updated
Aug 4, 2024
Vendor
GitLab
Product
GitLab
Classifications
CWE-918, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 5, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>=14.2, <14.2.5
  2. Affected versionversion=>=14.3, <14.3.1
  3. Affected versionversion=>=8.15, <14.1.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

GitLab · GitLabversion=>=14.2, <14.2.5; version=>=14.3, <14.3.1; version=>=8.15, <14.1.7

Published CVSS scores

8.1NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
5.5NVDAV:N/AC:L/Au:S/C:P/I:P/A:N
6.5GitLabCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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