CVE-2026-98010

net/sched: drr: clamp quantum in change class

State: Published
Severity: Not scored
Published: Sep 25, 2026
Updated: Oct 19, 2026
Reserved: Sep 25, 2026

Description

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

net/sched: drr: clamp quantum in change class

drr_change_class() rejects explicit quantum==0 but falls back to psched_mtu() with no floor. With a crafted size table qdisc_pkt_len reaches ~2 GiB, so quantum=1 (or a zero psched_mtu on a headerless device) makes the deficit-refill loop spin under the qdisc lock.

Add clamp_t(u32, quantum, 256, 1<<20) after the zero reject and on the fallback path. The explicit-zero reject is preserved.

Conditions to recreate the bug: CONFIG_NET_SCH_DRR=y. Requires CAP_NET_ADMIN (namespace-local via unshare -Urn suffices).

tc qdisc add dev dummy0 root drr tc class add dev dummy0 parent 1: classid 1:1 drr quantum 1

Scores

The record has no CVSS score.

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	13d2a1d2b032de08d7dcab6a1edcd47802681f96 to before e2297bbf9cf6ece86f1d1f8c683517a994990f9eAffected 13d2a1d2b032de08d7dcab6a1edcd47802681f96 to before 560794ee6e040b6e1c4ac2b3c8909f341a4596eeAffected 13d2a1d2b032de08d7dcab6a1edcd47802681f96 to before 23fea7e6736b2e1c6f6f2f05cccf33d36834da73Affected 13d2a1d2b032de08d7dcab6a1edcd47802681f96 to before b464affe9f9dfe41ac48930c376e3fb8596651b0Affected 13d2a1d2b032de08d7dcab6a1edcd47802681f96 to before dc8b374214ef5bba4882bbd95b361e42555cfc0dAffected 13d2a1d2b032de08d7dcab6a1edcd47802681f96 to before d43cded350fe1218493ad3d37a276aff14108ae6Affected 13d2a1d2b032de08d7dcab6a1edcd47802681f96 to before 8f756ae1c87414ce9cc21b30e6e4c036d6e9e80bAffected 13d2a1d2b032de08d7dcab6a1edcd47802681f96 to before 8382abec0f1568d0a5590d75a3df92f23fcf5196Affected
LinuxLinux	2.6.29Affected before 2.6.29Not affected 5.10.271 through 5.10.Not affected 5.15.222 through 5.15.Not affected 6.1.189 through 6.1.Not affected 6.6.158 through 6.6.Not affected 6.12.111 through 6.12.Not affected 6.18.53 through 6.18.Not affected 7.2.7 through 7.2.*Not affected 7.3 and laterNot affected

Product

Versions

LinuxLinux

13d2a1d2b032de08d7dcab6a1edcd47802681f96 to before e2297bbf9cf6ece86f1d1f8c683517a994990f9eAffected
13d2a1d2b032de08d7dcab6a1edcd47802681f96 to before 560794ee6e040b6e1c4ac2b3c8909f341a4596eeAffected
13d2a1d2b032de08d7dcab6a1edcd47802681f96 to before 23fea7e6736b2e1c6f6f2f05cccf33d36834da73Affected
13d2a1d2b032de08d7dcab6a1edcd47802681f96 to before b464affe9f9dfe41ac48930c376e3fb8596651b0Affected
13d2a1d2b032de08d7dcab6a1edcd47802681f96 to before dc8b374214ef5bba4882bbd95b361e42555cfc0dAffected
13d2a1d2b032de08d7dcab6a1edcd47802681f96 to before d43cded350fe1218493ad3d37a276aff14108ae6Affected
13d2a1d2b032de08d7dcab6a1edcd47802681f96 to before 8f756ae1c87414ce9cc21b30e6e4c036d6e9e80bAffected
13d2a1d2b032de08d7dcab6a1edcd47802681f96 to before 8382abec0f1568d0a5590d75a3df92f23fcf5196Affected

LinuxLinux

2.6.29Affected
before 2.6.29Not affected
5.10.271 through 5.10.*Not affected
5.15.222 through 5.15.*Not affected
6.1.189 through 6.1.*Not affected
6.6.158 through 6.6.*Not affected
6.12.111 through 6.12.*Not affected
6.18.53 through 6.18.*Not affected
7.2.7 through 7.2.*Not affected
7.3 and laterNot affected

References

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