CVE-2026-90074
Description
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.
How to fix
- Linux Linux1f43e4dbc93b7d02761a024d5f895df823c07b72, f7942b2693bc24c7d609a03d06f97bee3b0bd96a, 6f1be05faecef4c0f9a008200209f66ef2e133f7, 435da3734a8e63d3067016accc977ed1d10aaaa0, 44dad8fe99b58a7fe2961e9eec6a5f07ace5b51f, 044fa2498bbc2900f0c48a6ef2fdd5b2bdfc3795, bf97fd2163ad1191ef8daa3d4df8372aee19e396, c86cd7ed0b0e44779a3d1683f03e4353baf4bdc9 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Linux Linux | ec97ecf1ebe485a17cd8395a5f35e6b80b57665a ≤ v < 1f43e4dbc93b7d02761a024d5f895df823c07b72, ec97ecf1ebe485a17cd8395a5f35e6b80b57665a ≤ v < f7942b2693bc24c7d609a03d06f97bee3b0bd96a, ec97ecf1ebe485a17cd8395a5f35e6b80b57665a ≤ v < 6f1be05faecef4c0f9a008200209f66ef2e133f7, ec97ecf1ebe485a17cd8395a5f35e6b80b57665a ≤ v < 435da3734a8e63d3067016accc977ed1d10aaaa0, ec97ecf1ebe485a17cd8395a5f35e6b80b57665a ≤ v < 44dad8fe99b58a7fe2961e9eec6a5f07ace5b51f, ec97ecf1ebe485a17cd8395a5f35e6b80b57665a ≤ v < 044fa2498bbc2900f0c48a6ef2fdd5b2bdfc3795, ec97ecf1ebe485a17cd8395a5f35e6b80b57665a ≤ v < bf97fd2163ad1191ef8daa3d4df8372aee19e396, ec97ecf1ebe485a17cd8395a5f35e6b80b57665a ≤ v < c86cd7ed0b0e44779a3d1683f03e4353baf4bdc9, 5.6 | 1f43e4dbc93b7d02761a024d5f895df823c07b72, f7942b2693bc24c7d609a03d06f97bee3b0bd96a, 6f1be05faecef4c0f9a008200209f66ef2e133f7, 435da3734a8e63d3067016accc977ed1d10aaaa0, 44dad8fe99b58a7fe2961e9eec6a5f07ace5b51f, 044fa2498bbc2900f0c48a6ef2fdd5b2bdfc3795, bf97fd2163ad1191ef8daa3d4df8372aee19e396, c86cd7ed0b0e44779a3d1683f03e4353baf4bdc9 |
Check your version
Choose the product and enter the version you run to see whether it falls in the affected range.
Attack Surface Management
See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.