CVE-2026-90074net/sched: fq_pie: clamp default quantum to avoid signed overflow
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- Not yet scored
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Oct 19, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from ec97ecf1ebe485a17cd8395a5f35e6b80b57665a before 1f43e4dbc93b7d02761a024d5f895df823c07b72; from ec97ecf1ebe485a17cd8395a5f35e6b80b57665a before f7942b2693bc24c7d609a03d06f97bee3b0bd96a; from ec97ecf1ebe485a17cd8395a5f35e6b80b57665a before 6f1be05faecef4c0f9a008200209f66ef2e133f7; from ec97ecf1ebe485a17cd8395a5f35e6b80b57665a before 435da3734a8e63d3067016accc977ed1d10aaaa0; from ec97ecf1ebe485a17cd8395a5f35e6b80b57665a before 44dad8fe99b58a7fe2961e9eec6a5f07ace5b51f; from ec97ecf1ebe485a17cd8395a5f35e6b80b57665a before 044fa2498bbc2900f0c48a6ef2fdd5b2bdfc3795; from ec97ecf1ebe485a17cd8395a5f35e6b80b57665a before bf97fd2163ad1191ef8daa3d4df8372aee19e396; from ec97ecf1ebe485a17cd8395a5f35e6b80b57665a before c86cd7ed0b0e44779a3d1683f03e4353baf4bdc9 | CNA record |
References
- https://git.kernel.org/stable/c/1f43e4dbc93b7d02761a024d5f895df823c07b72
- https://git.kernel.org/stable/c/f7942b2693bc24c7d609a03d06f97bee3b0bd96a
- https://git.kernel.org/stable/c/6f1be05faecef4c0f9a008200209f66ef2e133f7
- https://git.kernel.org/stable/c/435da3734a8e63d3067016accc977ed1d10aaaa0
- https://git.kernel.org/stable/c/44dad8fe99b58a7fe2961e9eec6a5f07ace5b51f
- https://git.kernel.org/stable/c/044fa2498bbc2900f0c48a6ef2fdd5b2bdfc3795
- https://git.kernel.org/stable/c/bf97fd2163ad1191ef8daa3d4df8372aee19e396
- https://git.kernel.org/stable/c/c86cd7ed0b0e44779a3d1683f03e4353baf4bdc9
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.