CVE-2026-15007
MediumCVSS 5.7Exploitation Probability (EPSS)
Low risk19th percentile - higher than 19% of all known CVEs
Summary
A denial of service vulnerability in GitHub Enterprise Server allowed an authenticated user to disrupt the instance by supplying a deeply nested YAML release notes configuration file. During release notes generation, the file was parsed without a nesting depth limit, causing excessive resource consumption and rendering the instance unresponsive.
Risk Assessment
The risk is that an authenticated user can perform a DoS attack, potentially making the GitHub Enterprise Server instance unavailable to all users in the organization, disrupting development teams and CI/CD pipelines.
Recommendation
Immediately upgrade GitHub Enterprise Server to one of the patched versions: 3.17.18, 3.18.12, 3.19.9, 3.20.5, or 3.21.3. If upgrading is not possible, restrict access to the release notes generation feature to trusted users.
Other vulnerabilities in GitHub Enterprise Server
See all- CVE-2026-7541High
A denial of service vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to cause service disruption by sending crafted requests with deeply nested JSON payloads to an unauthenticated API endpoint. The endpoint parsed user-controlled JSON request bodies without size or depth limits.
- CVE-2026-17556Critical
GitHub Enterprise Server before version 3.22 has a path traversal vulnerability that allows an unauthenticated attacker to delete arbitrary files and directories on the instance, including the entire user storage directory containing Git LFS objects, release assets, attachments, and avatars. Exploitation of the X-GitHub-Request-Id header without sanitization as a filesystem path segment leads to data deletion.
- CVE-2026-9312High
GitHub Enterprise Server prior to version 3.22 has an SSRF vulnerability in an upload endpoint that allows an unauthenticated attacker to send crafted requests to internal services. By injecting path traversal content into request parameters, an attacker can bypass the intended request flow and redirect internal API calls.
- CVE-2026-15996High
GitHub Enterprise Server before version 3.21 contains a denial of service vulnerability that allows an unauthenticated attacker to cause excessive CPU consumption and exhaust the pool of request-handling worker processes by sending a crafted form-encoded HTTP POST request with deeply nested parameters. The vulnerability was fixed in versions 3.20.3, 3.19.7, 3.18.10, and 3.17.16.
- CVE-2026-15783Medium
A missing authorization vulnerability in GitHub Enterprise Server allowed an authenticated user with write access to any repository to read metadata from private repositories they did not have access to. The flaw enabled enumeration of rule identifiers and disclosure of repository names, branch names, commit SHAs, commit messages, and the pushing actor.
- CVE-2026-15343High
A path traversal vulnerability was found in GitHub Enterprise Server within the Dependabot updater container. An attacker with code execution in that container could write files to arbitrary repository paths, including GitHub Actions workflow files, potentially leading to secret theft.
- CVE-2026-14340Medium
An incorrect authorization vulnerability in GitHub Enterprise Server allowed a user-to-server token scoped to a GitHub App installation to perform write operations on public repositories outside its intended scope. An attacker with a stolen token could create issues, comments, and private vulnerability reports, impersonating the victim without app involvement.
- CVE-2026-10585Medium
A stored cross-site scripting vulnerability was found in GitHub Enterprise Server, allowing an authenticated attacker to execute arbitrary JavaScript in another user's browser by injecting a malicious payload into the title of a Discussion in the Q&A category. The AnsweredQuestionStructuredDataComponent failed to escape user-controlled Discussion titles before embedding them in a <script type="application/ld+json"> block, enabling breakout from the script context. The attack was escalated to full XSS by leveraging JSONP callback support in the REST API to bypass Content Security Policy.
- CVE-2026-9132Medium
A missing authorization vulnerability in GitHub Enterprise Server allowed an authenticated user to read source code from private repositories they did not have access to via the Copilot pull request description diff summary endpoint. The vulnerability affects all versions prior to 3.21 and was fixed in versions 3.17.17, 3.18.11, 3.19.8, and 3.20.4.
- CVE-2026-9106Medium
A UI misrepresentation vulnerability in GitHub Enterprise Server allowed an OAuth application to gain unintended access to an organization's runner management. The issue occurred because the manage_runners:org scope was not displayed on the authorization consent screen, enabling an attacker to trick a user into authorizing a malicious app.
Original NVD description (English source)
A denial of service vulnerability was identified in GitHub Enterprise Server that allowed an authenticated user to cause service disruption by supplying a repository release notes configuration file containing deeply nested YAML. When release notes were generated, the configuration file was parsed without a nesting depth limit, causing excessive resource consumption that could render the instance unresponsive. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.17.18, 3.18.12, 3.19.9, 3.20.5, and 3.21.3. This vulnerability was reported via the GitHub Bug Bounty program.

