5.5

CVE-2023-53421: blk-cgroup: Reinit blkg_iostat_set after clearing in blkcg_reset_stats()

Modified
AliasesUBUNTU-CVE-2023-53421DEBIAN-CVE-2023-53421
Published 18-09-2025Last modified 01-06-2026

Vulnerability summary

CVE-2023-53421 is a medium (CVSS 5.5) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.17% chance of exploitation in the next 30 days, higher than 5.7% 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 (CVE.org)
EPSS score
0.17%
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 29 · Related 23
DLA-4476-1DSA-6127-1RHSA-2023:7077RHSA-2024:1404RHSA-2024:2394RHSA-2024:4823

Timeline

  1. 18-09-2025
    PublishedVulnerability first disclosed.
  2. 01-06-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: blk-cgroup: Reinit blkg_iostat_set after clearing in blkcg_reset_stats() When blkg_alloc() is called to allocate a blkcg_gq structure with the associated blkg_iostat_set's, there are 2 fields within blkg_iostat_set that requires proper initialization - blkg & sync. The former field was introduced by commit 3b8cc6298724 ("blk-cgroup: Optimize blkcg_rstat_flush()") while the later one was introduced by commit f73316482977 ("blk-cgroup: reimplement basic IO stats using cgroup rstat"). Unfortunately those fields in the blkg_iostat_set's are not properly re-initialized when they are cleared in v1's blkcg_reset_stats(). This can lead to a kernel panic due to NULL pointer access of the blkg pointer. The missing initialization of sync is less problematic and can be a problem in a debug kernel due to missing lockdep initialization. Fix these problems by re-initializing them after memory clearing.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.17%

Chance of exploitation in the next 30 days

Percentile

6%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.16% 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.

Ubuntu111 products
  • linux< 5.15.0-176.186
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 5.15.0-1105.112
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ f73316482977ac401ac37245c9df48079d4e11f3, < 58c135513562698f222a58ba07dbdfcfb268aa0d | ≥ f73316482977ac401ac37245c9df48079d4e11f3, < 0561aa6033dd181594116d705c41fc16e97161a2 | ≥ f73316482977ac401ac37245c9df48079d4e11f3, < 892faa76be894d324bf48b12a55c7af7be2bad83 | ≥ f73316482977ac401ac37245c9df48079d4e11f3, < b0d26283af612b9e0cc3188b0b88ad7fdea447e8 | ≥ f73316482977ac401ac37245c9df48079d4e11f3, < abbce7f82613ea5eeefd0fc3c1c8e449b9cef2a2 | ≥ f73316482977ac401ac37245c9df48079d4e11f3, < 3d2af77e31ade05ff7ccc3658c3635ec1bea0979 | 5.5
  • linux_kernel≥ 5.5, < 6.3.13 | ≥ 6.4, < 6.4.4
Debian1 product
  • linux< 6.1.162-1 | < 6.4.4-1

3 vendors · 114 products

References

23 links
Show all 23 references