CVE-2026-23230
Estado: ModificadaMedia (5.5)—
In the Linux kernel, the following vulnerability has been resolved:
smb: client: split cached_fid bitfields to avoid shared-byte RMW races
is_open, has_lease and on_list are stored in the same bitfield byte in struct cached_fid but are updated in different code paths that may run concurrently. Bitfield assignments generate byte read–modify–write operations (e.g. `orb $mask, addr` on x86_64), so updating one flag can restore stale values of the others.
To avoid this class of races, convert these flags to separate bool fields.
Detalles técnicos trazas, registros y código del informe original
A possible interleaving is:
CPU1: load old byte (has_lease=1, on_list=1)
CPU2: clear both flags (store 0)
CPU1: RMW store (old | IS_OPEN) -> reintroduces cleared bitsCVSS
- 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: 0.23%
- Percentil entre todas las CVEs puntuadas: 12
- 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
- NVD-CWE-noinfo
Referencias
- https://git.kernel.org/stable/c/3eaa22d688311c708b73f3c68bc6d0c8e3f0f77a
- https://git.kernel.org/stable/c/4386f6af8aaedd0c5ad6f659b40cadcc8f423828
- https://git.kernel.org/stable/c/4cfa4c37dcbcfd70866e856200ed8a2894cac578
- https://git.kernel.org/stable/c/569fecc56bfe4df66f05734d67daef887746656b
- https://git.kernel.org/stable/c/c4b9edd55987384a1f201d3d07ff71e448d79c1b
- https://git.kernel.org/stable/c/ec306600d5ba7148c9dbf8f5a8f1f5c1a044a241
- https://cert-portal.siemens.com/productcert/html/ssa-253495.html
JSON original (NVD)
Mostrar
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: split cached_fid bitfields to avoid shared-byte RMW races\n\nis_open, has_lease and on_list are stored in the same bitfield byte in\nstruct cached_fid but are updated in different code paths that may run\nconcurrently. Bitfield assignments generate byte read–modify–write\noperations (e.g. `orb $mask, addr` on x86_64), so updating one flag can\nrestore stale values of the others.\n\nA possible interleaving is:\n CPU1: load old byte (has_lease=1, on_list=1)\n CPU2: clear both flags (store 0)\n CPU1: RMW store (old | IS_OPEN) -> reintroduces cleared bits\n\nTo avoid this class of races, convert these flags to separate bool\nfields."
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"value": "Se ha resuelto la siguiente vulnerabilidad en el kernel de Linux:\n\nsmb: cliente: dividir los campos de bits de cached_fid para evitar condiciones de carrera RMW de bytes compartidos\n\nis_open, has_lease y on_list se almacenan en el mismo byte de campo de bits en la estructura cached_fid, pero se actualizan en diferentes rutas de código que pueden ejecutarse concurrentemente. Las asignaciones de campos de bits generan operaciones de lectura-modificación-escritura de bytes (p. ej., 'orb $mask, addr' en x86_64), por lo que al actualizar una bandera (flag) se puede restaurar valores obsoletos de las otras.\n\nUna posible intercalación es:\n CPU1: carga el byte antiguo (has_lease=1, on_list=1)\n CPU2: borra ambas banderas (almacena 0)\n CPU1: almacena RMW (old | IS_OPEN) -> reintroduce los bits borrados\n\nPara evitar esta clase de condiciones de carrera, hay que convertir estas banderas a campos bool separados."
}
],
"lastModified": "2026-06-17T10:21:08.820",
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