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.

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Advisories
Source ID Title
Ubuntu USN Ubuntu USN USN-8726-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8727-1 Linux kernel (OEM) vulnerabilities
Ubuntu USN Ubuntu USN USN-8728-1 Linux kernel (GCP) vulnerabilities
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Wed, 29 Jul 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate


Sun, 26 Jul 2026 03:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-476

Fri, 24 Jul 2026 18:30:00 +0000

Type Values Removed Values Added
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.
Title kernel/fork: clear PF_BLOCK_TS in copy_process()
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-08-17T04:52:05.134Z

Reserved: 2026-07-19T15:36:31.773Z

Link: CVE-2026-64253

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Analyzed

Published: 2026-07-24T16:16:55.017

Modified: 2026-08-17T05:17:23.850

Link: CVE-2026-64253

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-07-24T00:00:00Z

Links: CVE-2026-64253 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-04T15:00:14Z

Weaknesses