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CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-98012

net/sched: sfq: clamp quantum in change path

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Status
Published
Published
Updated
Assigning organization
Linux

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 products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 4919649699c5f4dbae08b8e2ed536fc9d6c3c2aa to < 4117c528b2de5fdc3e4a7e3626815b616a635cdcaffected
  • 548cf048b426729a7a1fa6acd1271c010c9a7380 to < f82fa6f10d4a69322cad0f7a4aa523ce6292a5a0affected
  • c49ac48fac51a6a54efd5963954d02bacf075085 to < 0692ce5a528df450d64e9f819054177e9d91076faffected
  • 58ae7465f0e7113d45aa88a66bf2d203c71c195e to < e4192bcf83aaab02129644ddf4656fd86e93751faffected
  • 82bd38bd5467ece1ee274b493f51326cf5220a5a to < f3820dce042a673fcb28cc31c87ee14257e21a17affected
  • e4650d7ae4252f67e997a632adfae0dd74d3a99a to < 534cd7ecbbc6e8a974f4003a5c1557439c6e0a72affected
  • e4650d7ae4252f67e997a632adfae0dd74d3a99a to < e6c1cb728e389354203a72bc77464c222a247aebaffected
  • e4650d7ae4252f67e997a632adfae0dd74d3a99a to < fb9f88a33c516ea5c0bcd9a22ca288b246b34567affected
  • 843cacb88f42f426973f1ed11c6fb562558efb27affected
  • 5.10.239 to < 5.10.271affected
  • 5.15.186 to < 5.15.222affected
  • 6.1.129 to < 6.1.189affected
  • 6.6.76 to < 6.6.158affected
  • 6.12.13 to < 6.12.111affected
  • 5.4.297 to < 5.5affected

Linux Linux

Default version status: affected

  • 6.13affected
  • 0 to < 6.13unaffected
  • 5.10.271 to ≤ 5.10.*unaffected
  • 5.15.222 to ≤ 5.15.*unaffected
  • 6.1.189 to ≤ 6.1.*unaffected
  • 6.6.158 to ≤ 6.6.*unaffected
  • 6.12.111 to ≤ 6.12.*unaffected
  • 6.18.53 to ≤ 6.18.*unaffected
  • 7.2.7 to ≤ 7.2.*unaffected
  • 7.3 to ≤ *unaffected

References