CVE-2026-55158 (GCVE-0-2026-55158)

Vulnerability from cvelistv5 – Published: 2026-09-15 14:47 – Updated: 2026-09-17 14:42
VLAI
Title
Conflibot: Command injection via crafted pull request branch names under pull_request_target
Summary
Conflibot warns in advance when merging a pull request will cause conflicts in other open pull requests. Prior to 1.2.1, src/index.ts builds git checkout, git merge, and git format-patch commands by interpolating the attacker-controlled pull request head.ref value into strings passed to exec. In the documented pull_request_target configuration, an attacker can open a pull request, including from a fork, whose branch name contains shell metacharacters, and the workflow automatically interprets those characters as commands without maintainer interaction. The commands execute on a runner with base-repository secrets and a write-scoped GITHUB_TOKEN, allowing arbitrary command execution, secret or token exfiltration, unauthorized pushes, and other token abuse. The fixed implementations in src/index.ts and src/conflibot.ts use execFile or spawn argument arrays, and the v2 line also uses numeric pull-request refs rather than branch names. This issue is fixed in versions 1.2.1 and 2.0.0.
Severity
9.1 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
SSVC
Exploitation: none Automatable: yes Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-17 14:42 UTC
CWE
  • CWE-78 - Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Assigner
GitHub_M CNA
References
Impacted products
Vendor Product Version
wktk conflibot Affected: < 1.2.1
Create a notification for this product.
Show details on NVD website
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