CVE-2026-98012
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
How to fix
- Linux Linux4117c528b2de5fdc3e4a7e3626815b616a635cdc, f82fa6f10d4a69322cad0f7a4aa523ce6292a5a0, 0692ce5a528df450d64e9f819054177e9d91076f, e4192bcf83aaab02129644ddf4656fd86e93751f, f3820dce042a673fcb28cc31c87ee14257e21a17, 534cd7ecbbc6e8a974f4003a5c1557439c6e0a72, e6c1cb728e389354203a72bc77464c222a247aeb, fb9f88a33c516ea5c0bcd9a22ca288b246b34567, 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 5.5 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Linux Linux | 4919649699c5f4dbae08b8e2ed536fc9d6c3c2aa ≤ v < 4117c528b2de5fdc3e4a7e3626815b616a635cdc, 548cf048b426729a7a1fa6acd1271c010c9a7380 ≤ v < f82fa6f10d4a69322cad0f7a4aa523ce6292a5a0, c49ac48fac51a6a54efd5963954d02bacf075085 ≤ v < 0692ce5a528df450d64e9f819054177e9d91076f, 58ae7465f0e7113d45aa88a66bf2d203c71c195e ≤ v < e4192bcf83aaab02129644ddf4656fd86e93751f, 82bd38bd5467ece1ee274b493f51326cf5220a5a ≤ v < f3820dce042a673fcb28cc31c87ee14257e21a17, e4650d7ae4252f67e997a632adfae0dd74d3a99a ≤ v < 534cd7ecbbc6e8a974f4003a5c1557439c6e0a72, e4650d7ae4252f67e997a632adfae0dd74d3a99a ≤ v < e6c1cb728e389354203a72bc77464c222a247aeb, e4650d7ae4252f67e997a632adfae0dd74d3a99a ≤ v < fb9f88a33c516ea5c0bcd9a22ca288b246b34567, 843cacb88f42f426973f1ed11c6fb562558efb27, 5.10.239 ≤ v < 5.10.271, 5.15.186 ≤ v < 5.15.222, 6.1.129 ≤ v < 6.1.189, 6.6.76 ≤ v < 6.6.158, 6.12.13 ≤ v < 6.12.111, 5.4.297 ≤ v < 5.5, 6.13 | 4117c528b2de5fdc3e4a7e3626815b616a635cdc, f82fa6f10d4a69322cad0f7a4aa523ce6292a5a0, 0692ce5a528df450d64e9f819054177e9d91076f, e4192bcf83aaab02129644ddf4656fd86e93751f, f3820dce042a673fcb28cc31c87ee14257e21a17, 534cd7ecbbc6e8a974f4003a5c1557439c6e0a72, e6c1cb728e389354203a72bc77464c222a247aeb, fb9f88a33c516ea5c0bcd9a22ca288b246b34567, 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 5.5 |
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