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Fencer Vulns
high 8.1

CVE-2023-31128 json

NextCloud Cookbook's pull-checks.yml workflow is vulnerable to OS Command Injection

published 2023-05-26 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-35452

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
3.3%
EPSS 3.3% chance of exploitation in 30 days, percentile 88%
public exploits
0
none known

Summary

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 injection. Since the permission is not restricted, the attacker has a write-access to the repository. This issue is fixed in commit a46d9855 on the `master` branch and commit 489bb744 on the `main-0.9.x` branch. There is no risk for the user of the app within the NextCloud server. This only affects the main repository and possible forks of it. Those who have forked the NextCloud Cookbook repository should make sure their forks are on the latest version to prevent code injection attacks and similar.

Patch / fix

  • nextcloud cookbook 0.9.19

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
21 mo ago

Exploit prediction

3.34% chance of exploitation in the next 30 days, higher than 88% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/nextcloud/cookbook/security/advisories/GHSA-c5pc-mf2f-xq8h referenced PoC, tagged "exploit" by a source, unverified
  • securitylab.github.com https://securitylab.github.com/research/github-actions-untrusted-input/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • nextcloud cookbook

Classification

Weakness
  • CWE-78 Improper Neutralization of Special Elements used in an OS Command

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.