How severe is CVE-2023-31436?

CVE-2023-31436 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2023-31436 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-31436?

CVE-2023-31436 affects Linux Linux Kernel. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2023-31436?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2023-31436 published?

CVE-2023-31436 was published on 2023-04-28 and last updated on 2026-06-17.

CVE-2023-31436

CVE-2023-31436 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.

Key facts

Severity: High (CVSS 3.x base score 7.8)
EPSS exploit prediction: 1% (44th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Linux Linux Kernel
Published: 2023-04-28
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2023-31436?: CVE-2023-31436 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2023-31436 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-31436?: CVE-2023-31436 affects Linux Linux Kernel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2023-31436?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2023-31436 published?: CVE-2023-31436 was published on 2023-04-28 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

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