CVE-2026-10585: CWE-79 Improper neutralization of input during web page generation ('cross-site scripting') in GitHub Enterprise Server
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. This vulnerability was reported via the GitHub Bug Bounty program https://bounty.github.com/ .
AI Analysis
Technical Summary
CVE-2026-10585 is a stored cross-site scripting vulnerability in GitHub Enterprise Server affecting versions 3.17.0, 3.18.0, 3.19.0, and 3.20.0. The vulnerability occurs because the AnsweredQuestionStructuredDataComponent does not properly escape user-supplied Discussion titles before embedding them in a <script type="application/ld+json"> block. This allows an attacker with authenticated access to inject crafted JavaScript payloads that execute in other users' browsers. The attack is escalated to a full XSS by exploiting JSONP callback support in the REST API, which bypasses the Content Security Policy. The vulnerability was reported through the GitHub Bug Bounty program and fixed in subsequent patch releases 3.20.4, 3.19.8, 3.18.11, and 3.17.17.
Potential Impact
An authenticated attacker can execute arbitrary JavaScript in the browsers of other users by injecting malicious payloads into Discussion titles. This can lead to session hijacking, unauthorized actions on behalf of users, or other client-side attacks. The vulnerability affects confidentiality and integrity of user sessions within GitHub Enterprise Server instances running affected versions.
Mitigation Recommendations
Fixes for this vulnerability are available in GitHub Enterprise Server versions 3.20.4, 3.19.8, 3.18.11, and 3.17.17. Users should upgrade to one of these patched versions to remediate the issue. No additional mitigations are indicated by the vendor advisory.
CVE-2026-10585: CWE-79 Improper neutralization of input during web page generation ('cross-site scripting') in GitHub Enterprise Server
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. This vulnerability was reported via the GitHub Bug Bounty program https://bounty.github.com/ .
CVSS v4.0
Score 6.3medium
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-10585 is a stored cross-site scripting vulnerability in GitHub Enterprise Server affecting versions 3.17.0, 3.18.0, 3.19.0, and 3.20.0. The vulnerability occurs because the AnsweredQuestionStructuredDataComponent does not properly escape user-supplied Discussion titles before embedding them in a <script type="application/ld+json"> block. This allows an attacker with authenticated access to inject crafted JavaScript payloads that execute in other users' browsers. The attack is escalated to a full XSS by exploiting JSONP callback support in the REST API, which bypasses the Content Security Policy. The vulnerability was reported through the GitHub Bug Bounty program and fixed in subsequent patch releases 3.20.4, 3.19.8, 3.18.11, and 3.17.17.
Potential Impact
An authenticated attacker can execute arbitrary JavaScript in the browsers of other users by injecting malicious payloads into Discussion titles. This can lead to session hijacking, unauthorized actions on behalf of users, or other client-side attacks. The vulnerability affects confidentiality and integrity of user sessions within GitHub Enterprise Server instances running affected versions.
Mitigation Recommendations
Fixes for this vulnerability are available in GitHub Enterprise Server versions 3.20.4, 3.19.8, 3.18.11, and 3.17.17. Users should upgrade to one of these patched versions to remediate the issue. No additional mitigations are indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_P
- Date Reserved
- 2026-06-01T19:08:05.407Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a443df227e9c79719767780
Added to database: 06/30/2026, 22:06:42 UTC
Last enriched: 06/30/2026, 22:21:38 UTC
Last updated: 06/30/2026, 22:47:34 UTC
Views: 4
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