CVE-2026-63802

Aliases:UBUNTU-CVE-2026-63802DEBIAN-CVE-2026-63802
Advisory lineage Upstream: 0 Downstream: 24
Analyzed
Published: 19 Jul 2026, 12:02
Last modified:17 Aug 2026, 04:51

Vulnerability Summary

Overall Risk (default)
medium
31/100
CVSS Score
7.8 HIGH
v3.1 (cve.org)
EPSS Score
0.13% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

19 Jul 2026, 12:02
Published
Vulnerability first disclosed
17 Aug 2026, 04:51
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: blk-cgroup: fix UAF in __blkcg_rstat_flush() When multiple blkgs in the same blkcg are released concurrently, a use-after-free can occur. The race happens when one blkg's __blkcg_rstat_flush() removes another blkg's iostat entries via llist_del_all(). The second blkg sees an empty list and proceeds to free itself while the first is still iterating over its entries. Move the flush from __blkg_release() (RCU callback) to blkg_release() (before call_rcu). This ensures the RCU grace period waits for any concurrent flush's rcu_read_lock() section to complete before freeing.

CVSS Metrics

  • v3.1•HIGH•Score: 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Trends

Current EPSS score: 0.13%• Percentile: 3%

Techniques & Countermeasures

  • CWE-416•Use After Free

    The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Affected Systems

  • debian•linux

    < 6.12.95-1 | < 7.1.3-1

  • ubuntu•linux

    all | all | < 7.0.0-31.31

  • ubuntu•linux-allwinner-5.19

    all

  • ubuntu•linux-aws

    all | all | < 7.0.0-1012.12

  • ubuntu•linux-aws-5.0

    all

  • ubuntu•linux-aws-5.11

    all

  • ubuntu•linux-aws-5.13

    all

  • ubuntu•linux-aws-5.19

    all

  • ubuntu•linux-aws-5.3

    all

  • ubuntu•linux-aws-5.8

    all

  • ubuntu•linux-aws-6.14

    all

  • ubuntu•linux-aws-6.17

    all

  • ubuntu•linux-aws-6.2

    all

  • ubuntu•linux-aws-6.5

    all

  • ubuntu•linux-aws-6.8

    all

  • ubuntu•linux-aws-7.0

    all | < 7.0.0-1012.12~24.04.1

  • ubuntu•linux-aws-fips

    all

  • ubuntu•linux-azure

    all | all | all

  • ubuntu•linux-azure-5.11

    all

  • ubuntu•linux-azure-5.13

    all

  • ubuntu•linux-azure-5.19

    all

  • ubuntu•linux-azure-5.3

    all

  • ubuntu•linux-azure-5.8

    all

  • ubuntu•linux-azure-6.11

    all

  • ubuntu•linux-azure-6.14

    all

  • ubuntu•linux-azure-6.17

    all

  • ubuntu•linux-azure-6.2

    all

  • ubuntu•linux-azure-6.5

    all

  • ubuntu•linux-azure-6.8

    all

  • ubuntu•linux-azure-7.0

    all

  • ubuntu•linux-azure-edge

    all

  • ubuntu•linux-azure-fde

    all | all | all

  • ubuntu•linux-azure-fde-5.19

    all

  • ubuntu•linux-azure-fde-6.14

    all

  • ubuntu•linux-azure-fde-6.17

    all

  • ubuntu•linux-azure-fde-6.2

    all

  • ubuntu•linux-azure-fde-6.8

    all

  • ubuntu•linux-azure-fde-7.0

    all

  • ubuntu•linux-azure-fips

    all

  • ubuntu•linux-azure-nvidia

    all

  • ubuntu•linux-azure-nvidia-6.14

    all

  • ubuntu•linux-bluefield

    all

  • ubuntu•linux-fips

    all

  • ubuntu•linux-gcp

    all | all | all | < 7.0.0-1011.11

  • ubuntu•linux-gcp-5.11

    all

  • ubuntu•linux-gcp-5.13

    all

  • ubuntu•linux-gcp-5.19

    all

  • ubuntu•linux-gcp-5.3

    all

  • ubuntu•linux-gcp-5.8

    all

  • ubuntu•linux-gcp-6.11

    all

Showing first 50 affected entries in server-rendered view.

References (14)