CVE-2025-8405Public exploitNetwork attack vector

Unauthorized actions via unescaped code flow HTML

Published Dec 11, 2025 · Updated Dec 11, 2025

Stored HTML injection in affected GitLab CE/EE 17.1, 18.5, and 18.6 releases allows remote authenticated users to act as other users. Vulnerability code-flow displays render attacker-supplied HTML from imported project data without sufficient output encoding, allowing crafted elements to invoke authenticated browser actions. Exploitation requires an authenticated attacker to supply a malicious code flow and another user to open its vulnerability display; resulting actions use that viewer's session privileges.

CVSS severity7.7
High
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored HTML injection in affected GitLab CE/EE 17.1, 18.5, and 18.6 releases allows remote authenticated users to act as other users. Vulnerability code-flow displays render attacker-supplied HTML from imported project data without sufficient output encoding, allowing crafted elements to invoke authenticated browser actions. Exploitation requires an authenticated attacker to supply a malicious code flow and another user to open its vulnerability display; resulting actions use that viewer's session privileges.

The record

CVE
CVE-2025-8405
Published
Dec 11, 2025
Updated
Dec 11, 2025
Vendor
GitLab
Product
GitLab
Classifications
CWE-116, T1189
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 11, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 11, 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=17.1 <18.4.6
  2. Affected versionversion=18.5 <18.5.4
  3. Affected versionversion=18.6 <18.6.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

GitLab · GitLabversion=17.1 <18.4.6; version=18.5 <18.5.4; version=18.6 <18.6.2

Published CVSS scores

7.7GitLab Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/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 exploitPublished

Weakness, pattern, technique

CWE-116Improper Encoding or Escaping of Output
T1189Drive-by Compromise

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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