Malicious code in mutex-plus (npm)
--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (a64e56572436d2ca889aa389887584bbeb3e67df09f30df6773cbfafc0188ca3) lib/Mutex.js contains a hidden branch inside runExclusive() that, when a callback object carries a meta.jobId whose sha256 equals a hardcoded value (6cdda0ba143b3bee5949d3d45d2145c53c02abfe0e742465cdce2c0393e94d7f), invokes decryptToFile() from an obfuscated helper lib/common.js to AES-256-GCM-decrypt the shipped lib/plusMutex.min.js using the caller-supplied jobId as the key, then spawns the decrypted file via `node` as a detached, stdio-ignored, windowsHide child process. lib/common.js is a string-array + index-rotation obfuscated module wrapping scryptSync + createDecipheriv + writeFileSync; it is required only from this hidden branch. lib/plusMutex.min.js (16.9 KB, sha256 903169c2602ad15ba2dbc3c1e791bd26561958508d7d8a7ce35fc7d53c6212e1) is the AES-256-GCM ciphertext; sibling files lib/plusMutex.min.d.js (862 KB) and lib/tryAcquireMutex.min.d.js use a fabricated `.d.js` extension (real TypeScript declarations are `.d.ts`) to disguise executable/binary content as declaration artifacts. A mutex primitive has no functional need for encrypted-at-rest sibling blobs, an obfuscated GCM decryptor, or a hash-gated detached node spawn. The construction gives whoever holds the correct jobId — the decryption key — remote code execution on any consumer of Mutex.runExclusive that receives a crafted callback object, with the payload undecryptable without that key.
Malicious code in mutex-plus (npm)
Description
--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (a64e56572436d2ca889aa389887584bbeb3e67df09f30df6773cbfafc0188ca3) lib/Mutex.js contains a hidden branch inside runExclusive() that, when a callback object carries a meta.jobId whose sha256 equals a hardcoded value (6cdda0ba143b3bee5949d3d45d2145c53c02abfe0e742465cdce2c0393e94d7f), invokes decryptToFile() from an obfuscated helper lib/common.js to AES-256-GCM-decrypt the shipped lib/plusMutex.min.js using the caller-supplied jobId as the key, then spawns the decrypted file via `node` as a detached, stdio-ignored, windowsHide child process. lib/common.js is a string-array + index-rotation obfuscated module wrapping scryptSync + createDecipheriv + writeFileSync; it is required only from this hidden branch. lib/plusMutex.min.js (16.9 KB, sha256 903169c2602ad15ba2dbc3c1e791bd26561958508d7d8a7ce35fc7d53c6212e1) is the AES-256-GCM ciphertext; sibling files lib/plusMutex.min.d.js (862 KB) and lib/tryAcquireMutex.min.d.js use a fabricated `.d.js` extension (real TypeScript declarations are `.d.ts`) to disguise executable/binary content as declaration artifacts. A mutex primitive has no functional need for encrypted-at-rest sibling blobs, an obfuscated GCM decryptor, or a hash-gated detached node spawn. The construction gives whoever holds the correct jobId — the decryption key — remote code execution on any consumer of Mutex.runExclusive that receives a crafted callback object, with the payload undecryptable without that key.
Affected software
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Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- MAL-2026-14282
- Osv Schema Version
- 1.7.4
- Aliases
- []
- Ecosystems
- ["npm"]
- Database Specific Severity
- null
- Cvss Version
- null
Threat ID: 6a85b4b4acd9273b49251555
Added to database: 08/19/2026, 13:50:44 UTC
Last updated: 08/19/2026, 13:51:31 UTC
Views: 1
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