5.5

CVE-2023-53624: net/sched: sch_fq: fix integer overflow of "credit"

Analyzed
AliasesUBUNTU-CVE-2023-53624DEBIAN-CVE-2023-53624
Published 07-10-2025Last modified 11-05-2026

Vulnerability summary

CVE-2023-53624 is a medium (CVSS 5.5) Integer Overflow or Wraparound vulnerability in linux. EPSS estimates a 0.21% chance of exploitation in the next 30 days, higher than 11% 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
0.21%
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 3 · Related 1
RHSA-2023:6583RHSA-2023:7077SUSE-SU-2025:4189-1

Timeline

  1. 07-10-2025
    PublishedVulnerability first disclosed.
  2. 11-05-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_fq: fix integer overflow of "credit" if sch_fq is configured with "initial quantum" having values greater than INT_MAX, the first assignment of "credit" does signed integer overflow to a very negative value. In this situation, the syzkaller script provided by Cristoph triggers the CPU soft-lockup warning even with few sockets. It's not an infinite loop, but "credit" wasn't probably meant to be minus 2Gb for each new flow. Capping "initial quantum" to INT_MAX proved to fix the issue. v2: validation of "initial quantum" is done in fq_policy, instead of open coding in fq_change() _ suggested by Jakub Kicinski

CVSS metrics

4 scores · 3 sources · 2 versions

EPSS trend

Probability

0.21%

Chance of exploitation in the next 30 days

Percentile

11%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.20% 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.

Ubuntu123 products
  • linuxAll versions (No fix recorded) | < 5.15.0-79.86
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 5.15.0-1042.47
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ afe4fd062416b158a8a8538b23adc1930a9b88dc, < 4b8a05e3801661a0438fcd0cdef181030d966a5a | ≥ afe4fd062416b158a8a8538b23adc1930a9b88dc, < d0b43125ec892aeb1b03e5df5aab595097da225a | ≥ afe4fd062416b158a8a8538b23adc1930a9b88dc, < 4fbefeab88c6e79753a25099d455d3d59d2946b4 | ≥ afe4fd062416b158a8a8538b23adc1930a9b88dc, < 85f24cb2f10b2b0f2882e5786a09b4790bb3a0ad | ≥ afe4fd062416b158a8a8538b23adc1930a9b88dc, < 2322462d6f9ad4874f4e3c63df3b5cc00cb1acbd | ≥ afe4fd062416b158a8a8538b23adc1930a9b88dc, < 7041101ff6c3073fd8f2e99920f535b111c929cb | 3.12
  • linux_kernel≥ 3.12, < 5.10.180 | ≥ 5.11, < 5.15.111 | ≥ 5.16, < 6.1.28 | ≥ 6.2, < 6.2.15 | ≥ 6.3, < 6.3.2
Debian1 product
  • linux< 6.1.37-1 | < 6.3.7-1

3 vendors · 126 products

References

10 links