---
id: CVE-2026-55158
title: >-
  Conflibot warns in advance when merging a pull request will cause conflicts in
  other open pull requests
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 …
severity: critical
cvss: 9.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-78
vendor: wktk
product: conflibot
affected:
  - conflibot < 1.2.1
patched:
  - wktk/conflibot 1.2.1
published: '2026-09-15'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T15:16:48.047'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-55158'
references:
  - url: >-
      https://github.com/wktk/conflibot/commit/0107ac6a4575ea200d0b92287ea58f975be9505d
    label: security-advisories@github.com
  - url: >-
      https://github.com/wktk/conflibot/commit/59e255c49c920fd6b67471ab9ef3bf194439a3f2
    label: security-advisories@github.com
  - url: 'https://github.com/wktk/conflibot/pull/329'
    label: security-advisories@github.com
  - url: 'https://github.com/wktk/conflibot/releases/tag/v1.2.1'
    label: security-advisories@github.com
  - url: 'https://github.com/wktk/conflibot/releases/tag/v2.0.0'
    label: security-advisories@github.com
  - url: 'https://github.com/wktk/conflibot/security/advisories/GHSA-2qvg-qr73-mqxp'
    label: security-advisories@github.com
  - url: 'https://github.com/wktk/conflibot/commit/0107ac6'
  - url: 'https://github.com/wktk/conflibot/commit/59e255c'
  - url: 'https://github.com/advisories/GHSA-2qvg-qr73-mqxp'
tags:
  - nvd
  - cve.org
  - ghsa
  - actions
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-09-17T14:42:13.306848Z'
epss: 0.00445
epssPercentile: 0.38078
aliases:
  - GHSA-2qvg-qr73-mqxp
ecosystem: actions
ingestedAt: '2026-08-17T13:54:47.924Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-55158)

Affected packages:

- `wktk/conflibot < 1.2.1`

Patched in:

- `wktk/conflibot 1.2.1`

Source: https://github.com/advisories/GHSA-2qvg-qr73-mqxp