CVE-2023-31128 — NextCloud Cookbook is a recipe library app

NextCloud Cookbook is a recipe library app. Prior to commit a46d9855 on the `master` branch and commit 489bb744 on the `main-0.9.x` branch, the `pull-checks.yml` workflow is vulnerable to command injection attacks because of using an untrusted `github.head_ref` field. The `github

01What is this vulnerability?

NextCloud Cookbook is a recipe library app. Prior to commit a46d9855 on the `master` branch and commit 489bb744 on the `main-0.9.x` branch, the `pull-checks.yml` workflow is vulnerable to command injection attacks because of using an untrusted `github.head_ref` field. The `github.head_ref` value is an attacker-controlled value. Assigning the value to `zzz";echo${IFS}"hello";#` can lead to command…

02Affected products

Vendor	Product	Versions
nextcloud	cookbook	master < a46d9855, main-0.9.x < 489bb744

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2023-05-26T21:49:06.582Z
• Last modified: 2025-01-14T19:24:22.697Z

09References

• github.com — https://github.com/nextcloud/cookbook/security/advisories/GHSA-c5pc-mf2f-xq8h
• github.com — https://github.com/nextcloud/cookbook/commit/489bb744
• github.com — https://github.com/nextcloud/cookbook/commit/a46d98559e2c64292da9ffb06138cccc2e5…
• github.com — https://github.com/nextcloud/cookbook/blob/a14d6ffc4d45e1447556f68606129dfd6c150…
• securitylab.github.com — https://securitylab.github.com/research/github-actions-untrusted-input/