CVE-2026-46169
Estado: ModificadaMedia (5.5)—
In the Linux kernel, the following vulnerability has been resolved:
hfsplus: fix uninit-value by validating catalog record size
Syzbot reported a KMSAN uninit-value issue in hfsplus_strcasecmp(). The root cause is that hfs_brec_read() doesn't validate that the on-disk record size matches the expected size for the record type being read.
When mounting a corrupted filesystem, hfs_brec_read() may read less data than expected. For example, when reading a catalog thread record, the debug output showed:
hfs_brec_read() only validates that entrylength is not greater than the buffer size, but doesn't check if it's less than expected. It successfully reads 26 bytes into a 520-byte structure and returns success, leaving 494 bytes uninitialized.
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This uninitialized data in tmp.thread.nodeName then gets copied by hfsplus_cat_build_key_uni() and used by hfsplus_strcasecmp(), triggering the KMSAN warning when the uninitialized bytes are used as array indices in case_fold().
Fix by introducing hfsplus_brec_read_cat() wrapper that: 1. Calls hfs_brec_read() to read the data 2. Validates the record size based on the type field: - Fixed size for folder and file records - Variable size for thread records (depends on string length) 3. Returns -EIO if size doesn't match expected
For thread records, check against HFSPLUS_MIN_THREAD_SZ before reading nodeName.length to avoid reading uninitialized data at call sites that don't zero-initialize the entry structure.
Also initialize the tmp variable in hfsplus_find_cat() as defensive programming to ensure no uninitialized data even if validation is bypassed.
Detalles técnicos trazas, registros y código del informe original
HFSPLUS_BREC_READ: rec_len=520, fd->entrylength=26 HFSPLUS_BREC_READ: WARNING - entrylength (26) < rec_len (520) - PARTIAL READ!
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Puntuación base: 5.5
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.17%
- Percentil entre todas las CVEs puntuadas: 6
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
CWE
- CWE-908
Referencias
- https://git.kernel.org/stable/c/3003dbf62d151d47a6b90f71655292a51a05f244
- https://git.kernel.org/stable/c/3bc337697c66db2e2a4a94f0509c282c1a014b86
- https://git.kernel.org/stable/c/61a790974ff7e533acbceca06c7d02f22bf96d4d
- https://git.kernel.org/stable/c/8be69532e399eec9d9d990f6958b4ff2383b19b3
- https://git.kernel.org/stable/c/93e8d613f1a01b6637f387cc93f184cf7fb881d6
- https://git.kernel.org/stable/c/a420904450962a562ad053a41a53a27755021b48
- https://git.kernel.org/stable/c/b6b592275aeff184aa82fcf6abccd833fb71b393
- https://git.kernel.org/stable/c/c91bbd6193c70a02c50c22e0fb1f60c3c5bd053a
JSON original (NVD)
Mostrar
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nhfsplus: fix uninit-value by validating catalog record size\n\nSyzbot reported a KMSAN uninit-value issue in hfsplus_strcasecmp(). The\nroot cause is that hfs_brec_read() doesn't validate that the on-disk\nrecord size matches the expected size for the record type being read.\n\nWhen mounting a corrupted filesystem, hfs_brec_read() may read less data\nthan expected. For example, when reading a catalog thread record, the\ndebug output showed:\n\n HFSPLUS_BREC_READ: rec_len=520, fd->entrylength=26\n HFSPLUS_BREC_READ: WARNING - entrylength (26) < rec_len (520) - PARTIAL READ!\n\nhfs_brec_read() only validates that entrylength is not greater than the\nbuffer size, but doesn't check if it's less than expected. It successfully\nreads 26 bytes into a 520-byte structure and returns success, leaving 494\nbytes uninitialized.\n\nThis uninitialized data in tmp.thread.nodeName then gets copied by\nhfsplus_cat_build_key_uni() and used by hfsplus_strcasecmp(), triggering\nthe KMSAN warning when the uninitialized bytes are used as array indices\nin case_fold().\n\nFix by introducing hfsplus_brec_read_cat() wrapper that:\n1. Calls hfs_brec_read() to read the data\n2. Validates the record size based on the type field:\n - Fixed size for folder and file records\n - Variable size for thread records (depends on string length)\n3. Returns -EIO if size doesn't match expected\n\nFor thread records, check against HFSPLUS_MIN_THREAD_SZ before reading\nnodeName.length to avoid reading uninitialized data at call sites that\ndon't zero-initialize the entry structure.\n\nAlso initialize the tmp variable in hfsplus_find_cat() as defensive\nprogramming to ensure no uninitialized data even if validation is\nbypassed."
}
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"lastModified": "2026-06-19T13:16:34.600",
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