CVE-2023-49291: Improper Sanitization of Branch Name Leads to Arbitrary Code Injection

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2023-12-05 · updated 2026-06-17
Weakness: CWE-20

Description

tj-actions/branch-names is a Github action to retrieve branch or tag names with support for all events. The `tj-actions/branch-names` GitHub Actions improperly references the `github.event.pull_request.head.ref` and `github.head_ref` context variables within a GitHub Actions `run` step. The head ref variable is the branch name and can be used to execute arbitrary code using a specially crafted branch name. As a result an attacker can use this vulnerability to steal secrets from or abuse `GITHUB_TOKEN` permissions. This vulnerability has been addressed in version 7.0.7. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Affected products

tj-actions branch-names: before 7.0.0; from 7.0.1 before 7.0.7 — fixed in 7.0.0, 7.0.7

How to fix

Upgrade to a fixed version: tj-actions branch-names 7.0.0, 7.0.7. Check the vendor advisory for mitigations.

References

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