CVE-2026-84739Network attack vectorHinoki check available

Authenticated browser script execution via unsanitized diff paths

Published Sep 29, 2026 · Updated Sep 29, 2026

Cross-site scripting in GitLab CE/EE allows remote authenticated users to run JavaScript in another user's browser through a merge request diff. The diff viewer fails to sanitize path components before displaying them, allowing a crafted path to execute as script in the viewer's session. Exploitation requires an authenticated attacker and a separate user to view the affected merge request diff.

CVSS severity8.7
High
EPSS probability0.47%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Cross-site scripting in GitLab CE/EE allows remote authenticated users to run JavaScript in another user's browser through a merge request diff. The diff viewer fails to sanitize path components before displaying them, allowing a crafted path to execute as script in the viewer's session. Exploitation requires an authenticated attacker and a separate user to view the affected merge request diff.

The record

CVE
CVE-2026-84739
Published
Sep 29, 2026
Updated
Sep 29, 2026
Vendor
GitLab
Product
GitLab
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 29, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 29, 2026Record 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=13.11 <19.2.7
  2. Affected versionversion=19.3 <19.3.3
  3. Affected versionversion=19.4 <19.4.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

GitLab · GitLabversion=13.11 <19.2.7; version=19.3 <19.3.3; version=19.4 <19.4.1

Published CVSS scores

8.7GitLab CNACVSS:3.1/AV:N/AC:L/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.

Activity data is delayed. The latest report is Sep 28, 2026.

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

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript

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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