CVE-2021-39927Network attack vector

Authenticated localhost access via SSRF protection bypass

Published Jan 18, 2022 · Updated Aug 4, 2024

SSRF in affected GitLab CE/EE releases allows remote authenticated users to access localhost services through crafted requests. The SSRF protection permits requests to localhost on ports 80 and 443 when GitLab itself uses another port. Low-privileged network access and a nonstandard GitLab port are required, limiting exposure to data available from reachable local HTTP services.

CVSS severity3.5
Low
EPSS probability0.57%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in affected GitLab CE/EE releases allows remote authenticated users to access localhost services through crafted requests. The SSRF protection permits requests to localhost on ports 80 and 443 when GitLab itself uses another port. Low-privileged network access and a nonstandard GitLab port are required, limiting exposure to data available from reachable local HTTP services.

The record

CVE
CVE-2021-39927
Published
Jan 18, 2022
Updated
Aug 4, 2024
Vendor
GitLab
Product
GitLab
Classifications
CWE-918
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 18, 2022CVE 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=>=14.5, <14.5.3
  2. Affected versionversion=>=14.6, <14.6.2
  3. Affected versionversion=>=8.4, <14.4.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

GitLab · GitLabversion=>=14.5, <14.5.3; version=>=14.6, <14.6.2; version=>=8.4, <14.4.5

Published CVSS scores

4.3NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
3.5GitLab Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N
3.5NIST National Vulnerability DatabaseAV:N/AC:M/Au:S/C:N/I:P/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)

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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