CVE-2026-64251
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: pwrseq: core: fix use-after-free in pwrseq_debugfs_seq_next() pwrseq_debugfs_seq_next() declares 'next' with __free(put_device), which causes put_device() to be called on the returned pointer when the variable goes out of scope. This results in a use-after-free since the seq_file framework receives a pointer whose reference has already been dropped. Simply removing __free(put_device) would fix the UAF but would leak the reference acquired by bus_find_next_device(), as stop() only calls up_read(&pwrseq_sem) and never releases the device reference. Fix this by making the reference counting consistent across all seq_file callbacks, matching the standard pattern used by PCI and SCSI: - start(): use get_device() so it returns a referenced pointer. - next(): explicitly put_device(curr) to release the previous device's reference (no NULL check needed - the seq_file framework only calls next() while the previous return was non-NULL). - stop(): put_device(data) to release the last iterated device's reference, with a NULL guard since stop() may be called with NULL when start() returned NULL or next() reached end-of-sequence.
Severity
HIGH
CVSS score
7.8
(v3.1)
Vulnerability status
Analyzed
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-07-24 16:16:54.713000
Last modified
2026-11-08 20:10:00.187000
View original CVE JSON
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"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-07-24T16:16:54.713",
"lastModified": "2026-11-08T20:10:00.187",
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"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\npwrseq: core: fix use-after-free in pwrseq_debugfs_seq_next()\n\npwrseq_debugfs_seq_next() declares 'next' with __free(put_device),\nwhich causes put_device() to be called on the returned pointer when\nthe variable goes out of scope. This results in a use-after-free\nsince the seq_file framework receives a pointer whose reference has\nalready been dropped.\n\nSimply removing __free(put_device) would fix the UAF but would leak\nthe reference acquired by bus_find_next_device(), as stop() only\ncalls up_read(&pwrseq_sem) and never releases the device reference.\n\nFix this by making the reference counting consistent across all\nseq_file callbacks, matching the standard pattern used by PCI and\nSCSI:\n\n- start(): use get_device() so it returns a referenced pointer.\n- next(): explicitly put_device(curr) to release the previous\n device's reference (no NULL check needed - the seq_file framework\n only calls next() while the previous return was non-NULL).\n- stop(): put_device(data) to release the last iterated device's\n reference, with a NULL guard since stop() may be called with NULL\n when start() returned NULL or next() reached end-of-sequence."
},
{
"lang": "es",
"value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\npwrseq: core: corrección de uso después de liberación en pwrseq_debugfs_seq_next()\n\npwrseq_debugfs_seq_next() declara ’next’ con __free(put_device), lo que provoca que se llame a put_device() en el puntero devuelto cuando la variable sale de ámbito. Esto resulta en un uso después de liberación ya que el framework seq_file recibe un puntero cuya referencia ya ha sido liberada.\n\nSimplemente eliminar __free(put_device) corregiría el UAF pero fugaría la referencia adquirida por bus_find_next_device(), ya que stop() solo llama a up_read(&pwrseq_sem) y nunca libera la referencia del dispositivo.\n\nCorregir esto haciendo que el conteo de referencias sea consistente en todas las retrollamadas de seq_file, coincidiendo con el patrón estándar utilizado por PCI y SCSI:\n\n- start(): usar get_device() para que devuelva un puntero referenciado.\n- next(): llamar explícitamente a put_device(curr) para liberar la referencia del dispositivo anterior (no se necesita comprobación de NULL - el framework seq_file solo llama a next() mientras el retorno anterior no era NULL).\n- stop(): llamar a put_device(data) para liberar la referencia del último dispositivo iterado, con una protección contra NULL ya que stop() puede ser llamado con NULL cuando start() devolvió NULL o next() alcanzó el fin de secuencia."
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"source": "[email protected]",
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