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CVE-2026-98012

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Last modified

CVE-2026-98012 is a vulnerability of currently unknown severity. In the Linux kernel, the following vulnerability has been resolved: net/sched: sfq: clamp quantum in change path sfq_change() accepts any non-negative quantum (only rejects (int)ctl->quantum < 0). With a crafted size table qdisc_pkt_len reaches ~2 GiB, so quantum=1 makes the deficit-refill loop spin ~2^31 times under the qdisc lock (a soft lockup / denial of service). Add max(256U, ...) matching fq_codel_change().

Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: sfq: clamp quantum in change path sfq_change() accepts any non-negative quantum (only rejects (int)ctl->quantum < 0). With a crafted size table qdisc_pkt_len reaches ~2 GiB, so quantum=1 makes the deficit-refill loop spin ~2^31 times under the qdisc lock (a soft lockup / denial of service). Add max(256U, ...) matching fq_codel_change(). Reject quantum > 1<<20 with -EINVAL, matching fq_codel_change() and the init clamp. Conditions to recreate the bug: CONFIG_NET_SCH_SFQ=y. Requires CAP_NET_ADMIN (namespace-local via unshare -Urn suffices). tc qdisc add dev dummy0 root sfq tc qdisc change dev dummy0 root sfq quantum 1 stab data 32768 size_log 15 cell_log 0

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 82bd38bd5467ece1ee274b493f51326cf5220a5a, < f3820dce042a673fcb28cc31c87ee14257e21a17; >= e4650d7ae4252f67e997a632adfae0dd74d3a99a, < 534cd7ecbbc6e8a974f4003a5c1557439c6e0a72; >= e4650d7ae4252f67e997a632adfae0dd74d3a99a, < e6c1cb728e389354203a72bc77464c222a247aeb; >= e4650d7ae4252f67e997a632adfae0dd74d3a99a, < fb9f88a33c516ea5c0bcd9a22ca288b246b34567; 843cacb88f42f426973f1ed11c6fb562558efb27; 4919649699c5f4dbae08b8e2ed536fc9d6c3c2aa; 548cf048b426729a7a1fa6acd1271c010c9a7380; c49ac48fac51a6a54efd5963954d02bacf075085; 58ae7465f0e7113d45aa88a66bf2d203c71c195e; >= 6.12.13, < 6.12.111; >= 5.4.297, < 5.5; >= 5.10.239, < 5.11; >= 5.15.186, < 5.16; >= 6.1.129, < 6.2; >= 6.6.76, < 6.7
LinuxLinux6.13

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-98012?
In the Linux kernel, the following vulnerability has been resolved: net/sched: sfq: clamp quantum in change path sfq_change() accepts any non-negative quantum (only rejects (int)ctl->quantum < 0). With a crafted size table qdisc_pkt_len reaches ~2 GiB, so quantum=1 makes the deficit-refill loop spin ~2^31 times under the qdisc lock (a soft lockup / denial of service). Add max(256U, ...) matching fq_codel_change(). Reject quantum > 1<<20 with -EINVAL, matching fq_codel_change() and the init clamp. Conditions to recreate the bug: CONFIG_NET_SCH_SFQ=y. Requires CAP_NET_ADMIN (namespace-local via unshare -Urn suffices). tc qdisc add dev dummy0 root sfq tc qdisc change dev dummy0 root sfq quantum 1 stab data 32768 size_log 15 cell_log 0
How severe is CVE-2026-98012?
Severity scoring for CVE-2026-98012 is pending analysis.
How do I fix CVE-2026-98012?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST