GHSA-26gq-grmh-6xm6

Source

https://github.com/advisories/GHSA-26gq-grmh-6xm6

Import Source

https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/02/GHSA-26gq-grmh-6xm6/GHSA-26gq-grmh-6xm6.json

JSON Data

https://api.osv.dev/v1/vulns/GHSA-26gq-grmh-6xm6

Aliases

GO-2026-4454

Published

2026-02-06T19:44:14Z

Modified

2026-02-19T20:41:26Z

Severity

7.3 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N CVSS Calculator

Summary

Gogs vulnerable to Stored XSS via Mermaid diagrams

Details

Summary

Stored XSS via mermaid diagrams due to usage of vulnerable renderer library

Details

Gogs introduced support for rendering mermaid diagrams in version 0.13.0.

Currently used version of the library mermaid 11.9.0 is vulnerable to at least two XSS scenarios with publicly available payloads

Resources: https://github.com/mermaid-js/mermaid/security/advisories/GHSA-7rqq-prvp-x9jh https://github.com/mermaid-js/mermaid/security/advisories/GHSA-8gwm-58g9-j8pw

PoC

Create a markdown file eg. README.md containing following malicious mermaid diagram (payload based on CVE-2025-54880)

architecture-beta
    group api(cloud)[API]
    service db "<img src=x onerror=\"alert(document.domain)\">" [Database] in api

The XSS should pop whenever either repository or file is viewed

Demo

https://github.com/user-attachments/assets/98320f62-6c1c-4254-aa61-95598c725235

Impact

The attacker can potentially achieve account takeover In a worst case scenario if the victim were an instance admin this could lead to a compromise of the entire deployment

Proposed remediation steps

Upgrade to a patched version of the third party library https://github.com/mermaid-js/mermaid/releases/tag/v10.9.5
Consider running mermaid using sandbox level which would mitigate impact of future potential cross-site scripting issues https://mermaid.js.org/config/usage.html#securitylevel

Database specific

{
    "cwe_ids":  [
        "CWE-1395",
        "CWE-79"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2026-02-06T19:44:14Z",
    "nvd_published_at":  null,
    "severity":  "HIGH"
}

References

Affected packages

Go / gogs.io/gogs

Package

Name: gogs.io/gogs; View open source insights on deps.dev
Purl: pkg:golang/gogs.io/gogs

Affected ranges

Type: SEMVER
Events: Introduced

0 Unknown introduced version / All previous versions are affected

Fixed

0.13.4

Database specific

last_known_affected_version_range

"<= 0.13.3"

source

"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/02/GHSA-26gq-grmh-6xm6/GHSA-26gq-grmh-6xm6.json"