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FKIE_CVE-2026-55158

Vulnerability from fkie_nvd - Published: 2026-09-15 15:17 - Updated: 2026-09-15 15:17
Severity
9.1 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
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.
References
security-advisories@github.comhttps://github.com/wktk/conflibot/commit/0107ac6a4575ea200d0b92287ea58f975be9505d
security-advisories@github.comhttps://github.com/wktk/conflibot/commit/59e255c49c920fd6b67471ab9ef3bf194439a3f2
security-advisories@github.comhttps://github.com/wktk/conflibot/pull/329
security-advisories@github.comhttps://github.com/wktk/conflibot/releases/tag/v1.2.1
security-advisories@github.comhttps://github.com/wktk/conflibot/releases/tag/v2.0.0
security-advisories@github.comhttps://github.com/wktk/conflibot/security/advisories/GHSA-2qvg-qr73-mqxp
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "conflibot",
          "vendor": "wktk",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.2.1"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    }
  ],
  "id": "CVE-2026-55158",
  "lastModified": "2026-09-15T15:17:18.593",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 9.1,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.2,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-15T15:17:18.593",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/wktk/conflibot/commit/0107ac6a4575ea200d0b92287ea58f975be9505d"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/wktk/conflibot/commit/59e255c49c920fd6b67471ab9ef3bf194439a3f2"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/wktk/conflibot/pull/329"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/wktk/conflibot/releases/tag/v1.2.1"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/wktk/conflibot/releases/tag/v2.0.0"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/wktk/conflibot/security/advisories/GHSA-2qvg-qr73-mqxp"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-78"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}



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