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Vulnerabilities

Vulnerability · CVE-2023-31436

qfq_change_class in net/sched/sch_qfq.c in the Linux kernel before 6.2.13 allows an out-of-bounds write because lmax can exceed QFQ_MIN_LMAX.

Published Apr 28, 2023 · catalog updated Oct 14, 2026 · linux kernel

Check if you run it

No confirmed exploitation is on record for CVE-2023-31436. EPSS is 0.60%. Act only if a listed version of linux kernel is installed.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.60%
Remediation
Advisory link
Affected products
cpe linux/linux kernel

qfq_change_class in net/sched/sch_qfq.c in the Linux kernel before 6.2.13 allows an out-of-bounds write because lmax can exceed QFQ_MIN_LMAX.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe linux/linux kernelversion unspecified

How to fix CVE-2023-31436

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2023-31436. EPSS is 0.60%. Act only if a listed version of linux kernel is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-787: Out-of-bounds Write. EPSS 0.60%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 28, 2023 · NIST NVD

    Detected

    qfq_change_class in net/sched/sch_qfq.c in the Linux kernel before 6.2.13 allows an out-of-bounds write because lmax can exceed QFQ_MIN_LMAX.

  2. Oct 14, 2026 · NIST NVD

    Updated

    qfq_change_class in net/sched/sch_qfq.c in the Linux kernel before 6.2.13 allows an out-of-bounds write because lmax can exceed QFQ_MIN_LMAX.

Sources

  • CVE.orgVulnerability recordCVE-2023-31436

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2023-31436

    30-day exploitation probability 0.6%

    first.org
  • NIST NVDVulnerability recordCVE-2023-31436

    qfq_change_class in net/sched/sch_qfq.c in the Linux kernel before 6.2.13 allows an out-of-bounds write because lmax can exceed QFQ_MIN_LMAX.

    nvd.nist.gov
  • Packet Storm SecurityCited referencehttp://packetstormsecurity.com/files/173087/Kernel-Live-Patch-Security-Notice-LSN-0095-1.html

    Packet Storm link already published on the finding.

    packetstormsecurity.com
  • Packet Storm SecurityCited referencehttp://packetstormsecurity.com/files/173757/Kernel-Live-Patch-Security-Notice-LSN-0096-1.html

    Packet Storm link already published on the finding.

    packetstormsecurity.com
  • Packet Storm SecurityCited referencehttp://packetstormsecurity.com/files/175963/Kernel-Live-Patch-Security-Notice-LSN-0099-1.html

    Packet Storm link already published on the finding.

    packetstormsecurity.com

References

Freshness

Last verified in this catalog Oct 16, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.