CVE-2026-64253

kernel/fork: clear PF_BLOCK_TS in copy_process()

MEDIUM
5.5
CVSS Score
Published: July 24, 2026 at 03:31 PM UTC
Updated: August 17, 2026 at 05:17 AM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.1%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.13 ≤ v < 6.18.386.19 ≤ v < 7.1.36.9 ≤ v < 6.12.956.9 ≤ v < 6.18.386.9 ≤ v < 7.1.36.9 ≤ v < 7.26.96b23f92af87a84d70881b2ecaa72e0f7838264
Vendor states this is fixed in 77bba61a20f1b3d206f4f90e10a7bb3cd90b9619 (fixed)
Vendor states this is fixed in 99e6c712cc300883b8cbf03347d5359ec1a4d6dd (fixed)
Vendor states this is fixed in ee0801aceabdf583392477baf69a290b09448b8f (fixed)
Vendor states this is fixed in fd38b75c4b43295b10d69772a46d1c74dbd6fc81 (fixed)
Vendor states this is fixed in 6.12.95 (unaffected)
Vendor states this is fixed in 6.18.38 (unaffected)
Vendor states this is fixed in 6.9 (unaffected)
Vendor states this is fixed in 7.1.3 (unaffected)
Vendor states this is fixed in 7.2 (unaffected)

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-476

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