CVE-2026-55378Network attack vector

Runner command execution via untrusted pull request names

Published Aug 28, 2026 · Updated Aug 28, 2026

OS command injection in JS Recon allows remote attackers to execute commands on its GitHub Actions runner through a crafted pull request. The PR Branch Checker assigns pull request branch and fork names to BRANCH_NAME and SOURCE_REPO, then expands them unquoted inside a gh pr comment shell command. Exploitation requires a pull request targeting main; injected commands run with the workflow's pull-requests write token.

CVSS severity9.3
Critical
EPSS probability0.60%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

OS command injection in JS Recon allows remote attackers to execute commands on its GitHub Actions runner through a crafted pull request. The PR Branch Checker assigns pull request branch and fork names to BRANCH_NAME and SOURCE_REPO, then expands them unquoted inside a gh pr comment shell command. Exploitation requires a pull request targeting main; injected commands run with the workflow's pull-requests write token.

The record

CVE
CVE-2026-55378
Published
Aug 28, 2026
Updated
Aug 28, 2026
Vendor
Shriyans Sudhi
Product
JS Recon
Classifications
CWE-78, T1059
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 1.2.1-beta.1, < 1.3.1-beta.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Shriyans Sudhi · JS Reconversion=>= 1.2.1-beta.1, < 1.3.1-beta.2

Published CVSS scores

9.3GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059Command and Scripting Interpreter

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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