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CVE-2026-90074

net/sched: fq_pie: clamp default quantum to avoid signed overflow

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, and 2 more
None on Exploit-DB, Metasploit or GitHub

Summary

In the Linux kernel, the following vulnerability has been resolved: net/sched: fq_pie: clamp default quantum to avoid signed overflow fq_pie_init() sets q->quantum = psched_mtu(qdisc_dev(sch)) without clamping. A device with a huge MTU (e.g. dummy with max_mtu == 0 accepting MTU 2147483634) makes psched_mtu() return 0x80000000, which overflows the signed flow->deficit to INT_MIN in fq_pie_qdisc_dequeue(), causing an infinite loop and soft lockup. Emulate fq_pie_policy which is already bounded to [1, 1 << 20]; clamp the default to [256, 1 << 20]. 256 matches fq_codel's floor and is a sane minimum for a DRR quantum. Conditions to recreate the bug: a device whose MTU (plus hard_header_len) wraps psched_mtu() into the sign bit (e.g. a dummy device with max_mtu == 0 accepting MTU 2147483634). Requires CAP_NET_ADMIN in a user namespace.

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux Linux

    From ec97ecf1ebe485a17cd8395a5f35e6b80b57665a · fixed in 1f43e4dbc93b7d02761a024d5f895df823c07b72; From ec97ecf1ebe485a17cd8395a5f35e6b80b57665a · fixed in f7942b2693bc24c7d609a03d06f97bee3b0bd96a; From ec97ecf1ebe485a17cd8395a5f35e6b80b57665a · fixed in 6f1be05faecef4c0f9a008200209f66ef2e133f7; From ec97ecf1ebe485a17cd8395a5f35e6b80b57665a · fixed in 435da3734a8e63d3067016accc977ed1d10aaaa0; From ec97ecf1ebe485a17cd8395a5f35e6b80b57665a · fixed in 44dad8fe99b58a7fe2961e9eec6a5f07ace5b51f; From ec97ecf1ebe485a17cd8395a5f35e6b80b57665a · fixed in 044fa2498bbc2900f0c48a6ef2fdd5b2bdfc3795; From ec97ecf1ebe485a17cd8395a5f35e6b80b57665a · fixed in bf97fd2163ad1191ef8daa3d4df8372aee19e396; From ec97ecf1ebe485a17cd8395a5f35e6b80b57665a · fixed in c86cd7ed0b0e44779a3d1683f03e4353baf4bdc9

  • Linux Linux

    5.6

  • KernelLinux

    From 5.6.0 · fixed in 5.10.270; From 5.11.0 · fixed in 5.15.221; From 5.16.0 · fixed in 6.1.188; From 6.2.0 · fixed in 6.6.157; From 6.7.0 · fixed in 6.12.110; From 6.13.0 · fixed in 6.18.52; From 6.19.0 · fixed in 7.2.6

References 8

git.kernel.org