CVE-2023-31128Public exploitNetwork attack vector

Workflow command execution via unquoted branch reference

Published May 26, 2023 · Updated Jan 14, 2025

OS command injection in Nextcloud Cookbook repository workflows allows remote authenticated users to execute commands through pull requests. The pull-checks.yml workflow inserts the attacker-controlled github.head_ref value directly into a shell script that forms a git checkout command. A GitHub account able to open a pull request can run commands with the workflow token and write to the repository, while installed Nextcloud apps are not exposed.

CVSS severity8.1
High
EPSS probability3.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

OS command injection in Nextcloud Cookbook repository workflows allows remote authenticated users to execute commands through pull requests. The pull-checks.yml workflow inserts the attacker-controlled github.head_ref value directly into a shell script that forms a git checkout command. A GitHub account able to open a pull request can run commands with the workflow token and write to the repository, while installed Nextcloud apps are not exposed.

The record

CVE
CVE-2023-31128
Published
May 26, 2023
Updated
Jan 14, 2025
Vendor
Nextcloud GmbH
Product
Cookbook
Classifications
CWE-78, T1059.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 26, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 14, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=main-0.9.x < 489bb744
  2. Affected versionversion=master < a46d9855

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Nextcloud GmbH · Cookbookversion=main-0.9.x < 489bb744; version=master < a46d9855

Published CVSS scores

8.1GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059.004Unix Shell

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo