CVE-2026-64253 – kernel/fork: clear PF_BLOCK_TS in copy_process()

CVE ID :CVE-2026-64253

Published : July 24, 2026, 3:31 p.m. | 19 minutes ago

Description :In the Linux kernel, the following vulnerability has been resolved:

kernel/fork: clear PF_BLOCK_TS in copy_process()

PF_BLOCK_TS is only set in blk_time_get_ns() when current->plug is
non-NULL, and blk_finish_plug() clears it via __blk_flush_plug()
before NULLing the plug pointer. copy_process() breaks the
invariant by inheriting PF_BLOCK_TS from the parent while resetting
the child’s plug to NULL.

Clear PF_BLOCK_TS alongside that assignment so callers can rely on
“PF_BLOCK_TS set implies current->plug != NULL” and dereference
current->plug unguarded.

Severity: 0.0 | NA

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