CVE-2026-64012net/sched: sch_sfb: Replace direct dequeue call with peek and qdisc_dequeue_peeked

Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_sfb: Replace direct dequeue call with peek and qdisc_dequeue_peeked When sfb has children (eg qfq qdisc) whose peek() callback is qdisc_peek_dequeued(), we could get a kernel panic. When the parent of such qdiscs (eg illustrated in patch #3 as tbf) wants to retrieve an skb from its child (sfb in this case), it will do the following: 1a. do a peek() - and when sensing there's an skb the child can offer, then - the child in this case(sfb) calls its child's (qfq) peek. qfq does the right thing and will return the gso_skb queue packet. Note: if there wasnt a gso_skb entry then qfq will store it there. 1b. invoke a dequeue() on the child (sfb). And herein lies the problem. - sfb will call the child's dequeue() which will essentially just try to grab something of qfq's queue. [ 127.594489][ T453] KASAN: null-ptr-deref in range [0x0000000000000048-0x000000000000004f] [ 127.594741][ T453] CPU: 2 UID: 0 PID: 453 Comm: ping Not tainted 7.1.0-rc1-00035-gac961974495b-dirty #793 PREEMPT(full) [ 127.595059][ T453] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 127.595254][ T453] RIP: 0010:qfq_dequeue+0x35c/0x1650 [sch_qfq] [ 127.595461][ T453] Code: 00 fc ff df 80 3c 02 00 0f 85 17 0e 00 00 4c 8d 73 48 48 89 9d b8 02 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f 85 76 0c 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b [ 127.596081][ T453] RSP: 0018:ffff88810e5af440 EFLAGS: 00010216 [ 127.596337][ T453] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: dffffc0000000000 [ 127.596623][ T453] RDX: 0000000000000009 RSI: 0000001880000000 RDI: ffff888104fd82b0 [ 127.596917][ T453] RBP: ffff888104fd8000 R08: ffff888104fd8280 R09: 1ffff110211893a3 [ 127.597165][ T453] R10: 1ffff110211893a6 R11: 1ffff110211893a7 R12: 0000001880000000 [ 127.597404][ T453] R13: ffff888104fd82b8 R14: 0000000000000048 R15: 0000000040000000 [ 127.597644][ T453] FS: 00007fc380cbfc40(0000) GS:ffff88816f2a8000(0000) knlGS:0000000000000000 [ 127.597956][ T453] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 127.598160][ T453] CR2: 00005610aa9890a8 CR3: 000000010369e000 CR4: 0000000000750ef0 [ 127.598390][ T453] PKRU: 55555554 [ 127.598509][ T453] Call Trace: [ 127.598629][ T453] <TASK> [ 127.598718][ T453] ? mark_held_locks+0x40/0x70 [ 127.598890][ T453] ? srso_alias_return_thunk+0x5/0xfbef5 [ 127.599053][ T453] sfb_dequeue+0x88/0x4d0 [ 127.599174][ T453] ? ktime_get+0x137/0x230 [ 127.599328][ T453] ? srso_alias_return_thunk+0x5/0xfbef5 [ 127.599480][ T453] ? qdisc_peek_dequeued+0x7b/0x350 [sch_qfq] [ 127.599670][ T453] ? srso_alias_return_thunk+0x5/0xfbef5 [ 127.599831][ T453] tbf_dequeue+0x6b1/0x1098 [sch_tbf] [ 127.599988][ T453] __qdisc_run+0x169/0x1900 The right thing to do in #1b is to grab the skb off gso_skb queue. This patchset fixes that issue by changing #1b to use qdisc_dequeue_peeked() method instead.

Timeline

Scores

EPSS (exploitation in 30 days)

0.12% · top 98% of all CVEs (14 Nov 2026)

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.5.

Affected products

• Linux · Linux

  • affected e13e02a3c68d899169c78d9a18689bd73491d59a – < e5ea51e5f3fbba41d50cd84a530f33bc1c8f4d57
  • affected e13e02a3c68d899169c78d9a18689bd73491d59a – < 1e70274d3b81de28973bcdbce40a512bcb181ff9
  • affected e13e02a3c68d899169c78d9a18689bd73491d59a – < e125f5980b730c67c92a30cf150ec8c3d6777318
  • affected e13e02a3c68d899169c78d9a18689bd73491d59a – < 6c153d97c100f5b282c424101d8ff63122306997
  • affected e13e02a3c68d899169c78d9a18689bd73491d59a – < 84bfbfc0c48731bcce74cdf4f9c497547ec525e0
  • affected e13e02a3c68d899169c78d9a18689bd73491d59a – < dbc560858da8b77dd9e4ef0cd93d421e0e4d7e0e
  • affected e13e02a3c68d899169c78d9a18689bd73491d59a – < 9ad3288632c859cf84183199832d822e7a70bdae
  • affected e13e02a3c68d899169c78d9a18689bd73491d59a – < 1b9bc71153b01dbde8045b9edede4240f4f5520e

• Linux · Linux

  • affected 2.6.39
  • unaffected < 2.6.39
  • unaffected 5.10.259 – ≤ 5.10.*
  • unaffected 5.15.210 – ≤ 5.15.*
  • unaffected 6.1.176 – ≤ 6.1.*
  • unaffected 6.6.143 – ≤ 6.6.*
  • unaffected 6.12.93 – ≤ 6.12.*
  • unaffected 6.18.35 – ≤ 6.18.*
  • unaffected 7.0.12 – ≤ 7.0.*
  • unaffected 7.1 – ≤ *

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2026-45585 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

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Record last updated 19 Jul 2026, 14:56 UTC.