CVE-2026-15343 Path traversal vulnerability in GitHub Enterprise Server allowed writing files to arbitrary repository paths, including GitHub Actions workflow files, via unchecked Dependabot dependency-file paths

Description

A path traversal vulnerability was identified in GitHub Enterprise Server that allowed an attacker with code execution inside a Dependabot updater container to write files to arbitrary repository paths, including GitHub Actions workflow files under .github/workflows/, because path validation did not check the actual write destination. The initial fix in versions 3.21.3, 3.20.5, 3.19.9, 3.18.12, and 3.17.18 was incomplete because validation checked the supplied symlink target, while the publisher wrote the file using its directory and name. Writing GitHub Actions workflow files required the Dependabot installation to have workflows: write permission. Depending on repository permissions and workflow configuration, including a relevant pull_request_target workflow or auto-merge, an injected workflow could execute with access to GitHub Actions secrets. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.23 and was fully fixed in versions 3.22.3, 3.21.8, 3.20.10, and 3.19.14. This vulnerability was reported via the GitHub Bug Bounty program.

Exploitable remotely over the network, with an ordinary account and without any user action; an attacker can seriously compromise confidentiality, integrity or availability.

Attack vector

Network

Attack complexity

Low

Attack requirements

None

Privileges required

Low

Interaction

None

Confidentiality

High

Integrity

High

Availability

None

Confidentiality of other systems

None

Integrity of other systems

None

Availability of other systems

None

Affected products and versions