Stored XSS in GHES v<3.21 via AnsweredQuestionStructuredDataComponent
CVE-2026-10585 Published on June 30, 2026
Stored cross-site scripting vulnerability in GitHub Enterprise Server allowed arbitrary JavaScript execution via crafted Discussion titles in the Q&A category
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.
Vulnerability Analysis
CVE-2026-10585 can be exploited with network access. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.
Weakness Type
What is a XSS Vulnerability?
The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
CVE-2026-10585 has been classified to as a XSS vulnerability or weakness.
Products Associated with CVE-2026-10585
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Affected Versions
GitHub Enterprise Server:- Version 3.17.0, <= 3.17.16 is affected.
- Version 3.18.0, <= 3.18.10 is affected.
- Version 3.19.0, <= 3.19.7 is affected.
- Version 3.20.0, <= 3.20.3 is affected.
- Version 3.16.0, <= 3.16.19 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.