CVE-2025-12653Network attack vector

Unauthorized organization membership via spoofed request headers

Published Nov 26, 2025 · Updated Dec 10, 2025

Authentication bypass in GitLab CE/EE allows remote attackers to join arbitrary organizations through crafted account-registration requests. The account-registration path accepts changed request headers when assigning organization membership; GitLab has not disclosed the exact header or internal validation error. Reachability depends on vendor-undisclosed specific conditions, and successful requests grant organization membership without reported service interruption.

CVSS severity6.5
Medium
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in GitLab CE/EE allows remote attackers to join arbitrary organizations through crafted account-registration requests. The account-registration path accepts changed request headers when assigning organization membership; GitLab has not disclosed the exact header or internal validation error. Reachability depends on vendor-undisclosed specific conditions, and successful requests grant organization membership without reported service interruption.

The record

CVE
CVE-2025-12653
Published
Nov 26, 2025
Updated
Dec 10, 2025
Vendor
GitLab
Product
GitLab
Classifications
CWE-290, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 26, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 10, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=18.3 <18.4.5
  2. Affected versionversion=18.5 <18.5.3
  3. Affected versionversion=18.6 <18.6.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

GitLab · GitLabversion=18.3 <18.4.5; version=18.5 <18.5.3; version=18.6 <18.6.1

Published CVSS scores

6.5GitLab Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-290Authentication Bypass by Spoofing
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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