CVE-2026-55158

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.8% (55th percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.8%CVSS: 9.1Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
9.1
EG Score
9.1CRITICALmedium confidence
EG Risk
56
EG Risk 56/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity91% × 45%
Exploitation1% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.8%
EPSS %ILE
55th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 17, 2026

Last Modified

September 29, 2026

Advisory Details (6)

Auto-updated Sep 15, 2026
Patch available. Sources: github_pr, github_release, github, github_commit.
github Patch Available

Command injection via crafted pull request branch names under pull_request_target · Advisory · wktk/conflibot · GitHub

https://github.com/wktk/conflibot/security/advisories/GHSA-2qvg-qr73-mqxp
github_release Patch Available

v2.0.0

Patch available: wktk/conflibot v2.0.0

https://github.com/wktk/conflibot/releases/tag/v2.0.0
github_release Patch Available

v1.2.1

Patch available: wktk/conflibot v1.2.1

https://github.com/wktk/conflibot/releases/tag/v1.2.1
github_pr Patch Available

Release v2.0.0

Patch available: wktk/conflibot v2.0.0 (PR #329 merged 2026-06-10)

https://github.com/wktk/conflibot/pull/329
github_commit Patch Available

commit 59e255c49c92 (wktk/conflibot)

Patch available: wktk/conflibot v1.2.1 (contains commit 59e255c49c92)

https://github.com/wktk/conflibot/commit/59e255c49c920fd6b67471ab9ef3bf194439a3f2
github_commit Patch Available

commit 0107ac6a4575 (wktk/conflibot)

Patch available: wktk/conflibot v2.0.0 (contains commit 0107ac6a4575)

https://github.com/wktk/conflibot/commit/0107ac6a4575ea200d0b92287ea58f975be9505d

Vendor Advisories for CVE-2026-55158(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 14× in last 7d / 36× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-05 01:57 UTCEG score recompute
  2. 2026-10-04 23:22 UTCEPSS rescore
  3. 2026-10-03 17:49 UTCEG score recompute
  4. 2026-10-03 14:26 UTCEPSS rescore
  5. 2026-10-02 19:40 UTCEG score recompute
  6. 2026-10-02 17:56 UTCEPSS rescore
  7. 2026-10-02 01:35 UTCEG score recompute
  8. 2026-10-01 19:50 UTCEPSS rescore
  9. 2026-09-30 20:52 UTCEG score recompute
  10. 2026-09-30 15:03 UTCEPSS rescore
  11. 2026-09-29 19:25 UTCEG score recompute
  12. 2026-09-29 15:22 UTCEPSS rescore
  13. 2026-09-28 21:59 UTCEG score recompute
  14. 2026-09-28 13:51 UTCEPSS rescore
  15. 2026-09-27 16:29 UTCEG score recompute
  16. 2026-09-27 13:48 UTCEPSS rescore
  17. 2026-09-27 08:17 UTCEG score recompute
  18. 2026-09-26 15:59 UTCEPSS rescore
  19. 2026-09-24 16:14 UTCEG score recompute
  20. 2026-09-24 14:04 UTCEPSS rescore
  21. 2026-09-23 20:28 UTCEG score recompute
  22. 2026-09-23 17:54 UTCEPSS rescore
  23. 2026-09-22 20:41 UTCEG score recompute
  24. 2026-09-21 22:34 UTCEG score recompute
  25. 2026-09-20 22:35 UTCEG score recompute
Show 12 more
  1. 2026-09-20 20:16 UTCEPSS rescore
  2. 2026-09-19 18:49 UTCEG score recompute
  3. 2026-09-18 21:56 UTCEG score recompute
  4. 2026-09-18 19:28 UTCEPSS rescore
  5. 2026-09-17 21:56 UTCEG score recompute
  6. 2026-09-17 19:31 UTCEPSS rescore
  7. 2026-09-17 15:30 UTCEG score recompute
  8. 2026-09-17 14:49 UTCEG score recompute
  9. 2026-09-16 15:17 UTCEG score recompute
  10. 2026-09-16 14:08 UTCEPSS rescore
  11. 2026-09-15 15:34 UTCEG score recompute
  12. 2026-08-17 13:37 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-55158?
CVE-2026-55158 is a critical vulnerability published on August 17, 2026. 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…
When was CVE-2026-55158 disclosed?
CVE-2026-55158 was first published on August 17, 2026, with the most recent update on September 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55158 actively exploited?
CVE-2026-55158 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.8% probability of exploitation in the next 30 days (55th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-55158?
CVE-2026-55158 has a CVSS base score of 9.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-55158?
A fix for CVE-2026-55158 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-55158 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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