CVE-2026-3254 | BDVDB-2026-328246 Detail

GitLabGitLab

Description#

GitLab has remediated an issue in GitLab CE/EE affecting all versions from 18.11 before 18.11.1 that under certain conditions could have allowed an authenticated user to load unauthorized content into another user's browser due to improper input validation in the Mermaid sandbox.

Impact#

Per CVSS v3.1: confidentiality impact none, integrity impact low, availability impact none. Attack vector: network.

Weaknesses#

CWE-1021 Improper Restriction of Rendered UI Layers or Frames

References#

Exploit#

https://hackerone.com/reports/3572752

History#

Version 12026-04-22Record published in the CVE List.

Published

Published: 2026-04-22
Last modified: 2026-04-22

Vendor information

Vendor: GitLab
Product: GitLab

All GitLab vulnerabilities

Score

3.5 Low

EPSS

less than 1%, Very Low

Estimated chance of exploitation in the next 30 days. EPSS percentile: 4.4.

KEV

Not listed in the CISA Known Exploited Vulnerabilities catalog.

Impact

Not classified

Action

No specific action is recorded in the source data. Check the references for vendor guidance.

Affected Systems

Vulnerable
>= 18.11 and < 18.11.1
Fixed
18.11.1

Scoring System

CVSS v4.0

Not available

CVSS v3.1

3.5 Low

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N

Metric breakdown
Attack Vector	Network
Attack Complexity	Low
Privileges Required	Low
User Interaction	Required
Scope	Unchanged
Confidentiality	None
Integrity	Low
Availability	None

CVSS v3.0

Not available

CVSS v2

Not available

Source: CVE List v5 (record); CISA KEV (kev, action); FIRST EPSS (epss).