5.5

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

Analyzed
AliasesUBUNTU-CVE-2026-64253DEBIAN-CVE-2026-64253
Published 24-07-2026Last modified 17-08-2026

Vulnerability summary

CVE-2026-64253 is a medium (CVSS 5.5) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.11% chance of exploitation in the next 30 days, higher than 1.4% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.11%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 17 · Related 17
OPENSUSE-SU-2026:11476-1OPENSUSE-SU-2026:21910-1SUSE-SU-2026:23881-1SUSE-SU-2026:23887-1SUSE-SU-2026:23897-1SUSE-SU-2026:23902-1

Timeline

  1. 24-07-2026
    PublishedVulnerability first disclosed.
  2. 17-08-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.11%

Chance of exploitation in the next 30 days

Percentile

1%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.11% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu119 products
  • linux< 7.0.0-31.31
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 7.0.0-1012.12
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ 06b23f92af87a84d70881b2ecaa72e00f7838264, < ee0801aceabdf583392477baf69a290b09448b8f | ≥ 06b23f92af87a84d70881b2ecaa72e00f7838264, < 99e6c712cc300883b8cbf03347d5359ec1a4d6dd | ≥ 06b23f92af87a84d70881b2ecaa72e00f7838264, < 77bba61a20f1b3d206f4f90e10a7bb3cd90b9619 | ≥ 06b23f92af87a84d70881b2ecaa72e00f7838264, < fd38b75c4b43295b10d69772a46d1c74dbd6fc81 | 6.9
  • linux_kernel≥ 6.9, < 6.12.95 | ≥ 6.13, < 6.18.38 | ≥ 6.19, < 7.1.3
Debian1 product
  • linux< 6.12.95-1 | < 7.1.3-1

3 vendors · 122 products

References

19 links
Show all 19 references