CVE-2026-90073

net/sched: hhf: clamp quantum before hhf_change() to avoid overflow

State: Published
Severity: Not scored
Published: Sep 17, 2026
Updated: Oct 19, 2026
Reserved: Sep 11, 2026

Description

In the Linux kernel, the following vulnerability has been resolved:

net/sched: hhf: clamp quantum before hhf_change() to avoid overflow

hhf_init() sets q->quantum = psched_mtu(qdisc_dev(sch)) with no overflow check. A device with a huge MTU (e.g. dummy with max_mtu == 0 accepting MTU 2147483634) makes weight * quantum overflow the signed deficit in hhf_dequeue(), spinning forever.

Clamp q->quantum before hhf_change() so both the opt and !opt paths see a sane quantum. Without this, bare "tc qdisc add ... hhf" succeeds with a clamped quantum but "tc qdisc add ... hhf limit 1000" (any option present) fails with -EINVAL because hhf_change() re-validates the unclamped default (sch_hhf.c:559). 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.

Scores

The record has no CVSS score.

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	10239edf86f137ce4c39b62ea9575e8053c549a0 to before 2e0f0729f922c8de13801004e2131b57646c7c5fAffected 10239edf86f137ce4c39b62ea9575e8053c549a0 to before 0c66223e90ddb4fd3700965a9241f2fde7bd6bc7Affected 10239edf86f137ce4c39b62ea9575e8053c549a0 to before 20b65bf7ca06e48ec1d62ed8012f71205328dbe4Affected 10239edf86f137ce4c39b62ea9575e8053c549a0 to before dea2789a9d5ff38bdd77f2e64d550430899e2839Affected 10239edf86f137ce4c39b62ea9575e8053c549a0 to before fa9c2055f0a60f801ccf286af53d387dc6202c3fAffected 10239edf86f137ce4c39b62ea9575e8053c549a0 to before 99770b5d8e0e1c69b996f74a19d71afd2c4a9aa4Affected 10239edf86f137ce4c39b62ea9575e8053c549a0 to before 2446644b0f6d045b01db6acbaf55552dbec8a59aAffected 10239edf86f137ce4c39b62ea9575e8053c549a0 to before 2164b512b97bb053e8ce4d6e95576f11bed6a005Affected
LinuxLinux	3.14Affected before 3.14Not affected 5.10.270 through 5.10.Not affected 5.15.221 through 5.15.Not affected 6.1.188 through 6.1.Not affected 6.6.157 through 6.6.Not affected 6.12.110 through 6.12.Not affected 6.18.52 through 6.18.Not affected 7.2.6 through 7.2.*Not affected 7.3 and laterNot affected

Product

Versions

LinuxLinux

10239edf86f137ce4c39b62ea9575e8053c549a0 to before 2e0f0729f922c8de13801004e2131b57646c7c5fAffected
10239edf86f137ce4c39b62ea9575e8053c549a0 to before 0c66223e90ddb4fd3700965a9241f2fde7bd6bc7Affected
10239edf86f137ce4c39b62ea9575e8053c549a0 to before 20b65bf7ca06e48ec1d62ed8012f71205328dbe4Affected
10239edf86f137ce4c39b62ea9575e8053c549a0 to before dea2789a9d5ff38bdd77f2e64d550430899e2839Affected
10239edf86f137ce4c39b62ea9575e8053c549a0 to before fa9c2055f0a60f801ccf286af53d387dc6202c3fAffected
10239edf86f137ce4c39b62ea9575e8053c549a0 to before 99770b5d8e0e1c69b996f74a19d71afd2c4a9aa4Affected
10239edf86f137ce4c39b62ea9575e8053c549a0 to before 2446644b0f6d045b01db6acbaf55552dbec8a59aAffected
10239edf86f137ce4c39b62ea9575e8053c549a0 to before 2164b512b97bb053e8ce4d6e95576f11bed6a005Affected

LinuxLinux

3.14Affected
before 3.14Not affected
5.10.270 through 5.10.*Not affected
5.15.221 through 5.15.*Not affected
6.1.188 through 6.1.*Not affected
6.6.157 through 6.6.*Not affected
6.12.110 through 6.12.*Not affected
6.18.52 through 6.18.*Not affected
7.2.6 through 7.2.*Not affected
7.3 and laterNot affected

References

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.