CVE-2025-6454Public exploitNetwork attack vector

Authenticated SSRF via webhook header CRLF injection

Published Sep 12, 2025 · Updated Sep 12, 2025

Server-side request forgery in GitLab CE/EE allows remote authenticated users to reach internal services through webhook requests. Webhook custom-header names accept CRLF sequences, causing an outbound proxy to parse attacker-controlled header data as a second HTTP request. A configured forward proxy that permits HTTP pipelining is required, and the resulting access is blind rather than direct response disclosure.

CVSS severity8.5
High
EPSS probability0.69%
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 GitLab CE/EE allows remote authenticated users to reach internal services through webhook requests. Webhook custom-header names accept CRLF sequences, causing an outbound proxy to parse attacker-controlled header data as a second HTTP request. A configured forward proxy that permits HTTP pipelining is required, and the resulting access is blind rather than direct response disclosure.

The record

CVE
CVE-2025-6454
Published
Sep 12, 2025
Updated
Sep 12, 2025
Vendor
GitLab
Product
GitLab
Classifications
CWE-918, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 12, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 12, 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=16.11 <18.1.6
  2. Affected versionversion=18.2 <18.2.6
  3. Affected versionversion=18.3 <18.3.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

GitLab · GitLabversion=16.11 <18.1.6; version=18.2 <18.2.6; version=18.3 <18.3.2

Published CVSS scores

8.5GitLab Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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 exploitPublished

Weakness, pattern, technique

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

Public exploit references

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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