PT-2026-64366 · Linux · Linux

CVE-2026-64251 · Published 2026-07-24 · Updated 2026-07-24

Mitre

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.

Related Identifiers

CVE-2026-64251

Affected Products

Linux

References · 5

• https://nvd.nist.gov/vuln/detail/CVE-2026-64251 · Security Note
• https://git.kernel.org/stable/c/e91df6d273445c03f5aa302bfe147eda33d45794 · Note
• https://git.kernel.org/stable/c/73569a44fca2992f0ca4a4c0104069741b9873a0 · Note
• https://git.kernel.org/stable/c/257595adf9dac15ae1edd9d07753fbc576a7583d · Note
• https://git.kernel.org/stable/c/ba0b9f04c7a5f9887b8ce672eaf049502c0548ec · Note