CVE-2023-27581: github-slug-action is a GitHub Action to expose slug value of GitHub environment variables inside of one's Git

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HIGH 8.8UPGRADE

CVE-2023-27581 is a high-severity flaw (CVSS 8.8) affecting github-slug-action. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

github-slug-action is a GitHub Action to expose slug value of GitHub environment variables inside of one's GitHub workflow. Starting in version 4.0.0` and prior to version 4.4.1, this action uses the `github.head_ref` parameter in an insecure way. This vulnerability can be triggered by any user on GitHub on any workflow using the action on pull requests. They just need to create a pull request with a branch name, which can contain the attack payl

Why this priority

High severity
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	1.6% (top 25%)
CISA exploited list	No
Weakness	CWE-77
Published	2023-03-13
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: github-slug-action project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-03-13 21:15 UTCPublished CVE record published
2026-06-17 05:45 UTCUpdated Record last modified

github-slug-action project github-slug-action UPGRADE

Affected: >= 4.0.0 and < 4.4.1

Fixed in: 4.4.1

Safe to downgrade to: a release before 4.0.0

1. Check installed version

apt-cache policy github-slug-action || rpm -q github-slug-action || github-slug-action --version

2. UPGRADE to 4.4.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade github-slug-action

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade github-slug-action

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 4.0.0 (Debian / Ubuntu)

apt-cache madison github-slug-action sudo apt install github-slug-action=<VERSION_BEFORE_4.0.0> sudo apt-mark hold github-slug-action

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list github-slug-action sudo dnf downgrade github-slug-action-<VERSION_BEFORE_4.0.0> sudo dnf versionlock add github-slug-action

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-27581?

github-slug-action: upgrade to 4.4.1. Exact commands for each OS are on this page.

Is CVE-2023-27581 being exploited?

CVE-2023-27581 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-27581 affect?

CVE-2023-27581 affects github-slug-action. Severity is high (CVSS 8.8). github-slug-action is a GitHub Action to expose slug value of GitHub environment variables inside of one's GitHub workflow. Starting in version 4.0.0` and prior to version 4.4.1, this action uses the `github.head_ref` parameter in an insecu

How urgent is CVE-2023-27581?

Priority 55/100. High severity; Public exploit reference

Software pages

GitHub vulnerabilities · Git vulnerabilities

References

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