{"id":"CVE-2026-55158","state":"PUBLISHED","title":"Conflibot: Command injection via crafted pull request branch names under pull_request_target","description":"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.","publishedAt":"2026-09-15T14:47:58.804Z","updatedAt":"2026-09-17T14:42:35.993Z","severity":{"score":9.1,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["wktk conflibot"],"affected":[{"vendor":"wktk","product":"conflibot","versions":[{"version":"< 1.2.1","status":"affected"}]}],"references":["https://github.com/wktk/conflibot/security/advisories/GHSA-2qvg-qr73-mqxp","https://github.com/wktk/conflibot/pull/329","https://github.com/wktk/conflibot/commit/0107ac6a4575ea200d0b92287ea58f975be9505d","https://github.com/wktk/conflibot/commit/59e255c49c920fd6b67471ab9ef3bf194439a3f2","https://github.com/wktk/conflibot/releases/tag/v1.2.1","https://github.com/wktk/conflibot/releases/tag/v2.0.0"],"weaknesses":["CWE-78"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/55xxx/CVE-2026-55158.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-55158","state":"PUBLISHED","datePublished":"2026-09-15T14:47:58.804Z","dateUpdated":"2026-09-17T14:42:35.993Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-16T15:13:28.165Z"},"containers":{"cna":{"title":"Conflibot: Command injection via crafted pull request branch names under pull_request_target","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."}],"affected":[{"vendor":"wktk","product":"conflibot","versions":[{"version":"< 1.2.1","status":"affected"}]}],"references":[{"url":"https://github.com/wktk/conflibot/security/advisories/GHSA-2qvg-qr73-mqxp","name":"https://github.com/wktk/conflibot/security/advisories/GHSA-2qvg-qr73-mqxp","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/wktk/conflibot/pull/329","name":"https://github.com/wktk/conflibot/pull/329","tags":["x_refsource_MISC"]},{"url":"https://github.com/wktk/conflibot/commit/0107ac6a4575ea200d0b92287ea58f975be9505d","name":"https://github.com/wktk/conflibot/commit/0107ac6a4575ea200d0b92287ea58f975be9505d","tags":["x_refsource_MISC"]},{"url":"https://github.com/wktk/conflibot/commit/59e255c49c920fd6b67471ab9ef3bf194439a3f2","name":"https://github.com/wktk/conflibot/commit/59e255c49c920fd6b67471ab9ef3bf194439a3f2","tags":["x_refsource_MISC"]},{"url":"https://github.com/wktk/conflibot/releases/tag/v1.2.1","name":"https://github.com/wktk/conflibot/releases/tag/v1.2.1","tags":["x_refsource_MISC"]},{"url":"https://github.com/wktk/conflibot/releases/tag/v2.0.0","name":"https://github.com/wktk/conflibot/releases/tag/v2.0.0","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"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"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-78","lang":"en","description":"CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-09-15T14:47:58.804Z"},"source":{"advisory":"GHSA-2qvg-qr73-mqxp","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-17T14:42:13.306848Z","id":"CVE-2026-55158","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-17T14:42:35.993Z"}}]}}}