Vulnerability · Published Jun 30, 2026 · Assigned by GitHub_P
CVE-2026-10585Stored cross-site scripting vulnerability in GitHub Enterprise Server allowed arbitrary JavaScript execution via crafted Discussion titles in the Q&A category
Medium 6.3
In plain English
A medium-severity cross-site scripting in Enterprise Server from GitHub. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 25% of all known vulnerabilities).
Official description
A stored cross-site scripting vulnerability was identified in GitHub Enterprise Server that allowed an authenticated attacker to execute arbitrary JavaScript in another user's browser by injecting a crafted payload into the title of a Discussion in the Q&A category. The AnsweredQuestionStructuredDataComponent did not escape user-controlled Discussion titles before embedding them in a <script type="application/ld+json"> block, allowing the title to break out of the script context. The injection was escalated to a full cross-site scripting attack on GitHub Enterprise Server by leveraging JSONP callback support in the REST API to bypass the Content Security Policy. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.20.4, 3.19.8, 3.18.11, 3.17.17, 3.16.20. This vulnerability was reported via the GitHub Bug Bounty program.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| GitHub | Enterprise Server | 3.17.0 – through 3.17.163.18.0 – through 3.18.103.19.0 – through 3.19.73.20.0 – through 3.20.33.16.0 – through 3.16.19 |
Weakness: CWE-79 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:H/SI:H/SA:N
References
- https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.17
- https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.11
- https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.8
- https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.4
- https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.20