CVE-2026-80630

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-08-28. a secondary CVSS source baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 5 sources updated this week
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.8Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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

net/sched: sch_fq_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen

Whenever fq_codel drops packets during peek, it calls qdisc_tree_reduce_backlog. An issue arises because it calls qdisc_tree_reduce_backlog before it reincrements the qlen. If qlen drops to zero, but peek returns an skb, the parent's qlen_notify callback will be executed even though fq_codel still has 1 packet on the queue and, thus, will mistakenly deactivate the parent's class causing issues like a recent report [1] and a wild memory access in qfq:

[ 29.371146][ T360] Oops: general protection fault, probably for non-canonical address 0xfbd59c0000000024: 0000 [#1] SMP KASAN NOPTI [ 29.371666][ T360] KASAN: maybe wild-memory-access in range [0xdead000000000120-0xdead000000000127] [ 29.371987][ T360] CPU: 6 UID: 0 PID: 360 Comm: tc Not tainted 7.1.0-rc5-00285-gc530e5b2dbc6-dirty #82 PREEMPT(full) [ 29.372384][ T360] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 29.372620][ T360] RIP: 0010:qfq_deactivate_agg (include/linux/list.h:1029 (discriminator 2) include/linux/list.h:1043 (discriminator 2) net/sched/sch_qfq.c:1369 (discriminator 2) net/sched/sch_qfq.c:1395 (discriminator 2)) sch_qfq [ 29.373544][ T360] RSP: 0018:ffff888102417370 EFLAGS: 00010216 [ 29.373800][ T360] RAX: 0000000000000000 RBX: ffff88811224d568 RCX: dffffc0000000000 [ 29.374079][ T360] RDX: 1ffff11021fe1543 RSI: ffff88810ff0aa00 RDI: dffffc0000000000 [ 29.374368][ T360] RBP: ffff88811224c280 R08: dead000000000122 R09: 1bd5a00000000024 [ 29.374649][ T360] R10: fffffbfff7940329 R11: fffffbfff7940329 R12: 0000000000000000 [ 29.374926][ T360] R13: dead000000000100 R14: ffff88811224d580 R15: ffff88811224d578 [ 29.375207][ T360] FS: 00007f5b794e5780(0000) GS:ffff88815d1e9000(0000) knlGS:0000000000000000 [ 29.375545][ T360] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 29.375823][ T360] CR2: 000055ffb091f000 CR3: 000000010a305000 CR4: 0000000000750ef0 [ 29.376103][ T360] PKRU: 55555554 [ 29.376258][ T360] Call Trace: [ 29.376401][ T360] ... [ 29.376885][ T360] qfq_reset_qdisc (net/sched/sch_qfq.c:357 net/sched/sch_qfq.c:1487) sch_qfq [ 29.377074][ T360] qdisc_reset (net/sched/sch_generic.c:1057) [ 29.377414][ T360] __qdisc_destroy (net/sched/sch_generic.c:1096) [ 29.377600][ T360] qdisc_graft (net/sched/sch_api.c:1062 net/sched/sch_api.c:1053 net/sched/sch_api.c:1159) [ 29.378593][ T360] tc_get_qdisc (net/sched/sch_api.c:1528 net/sched/sch_api.c:1556)

Fix this by only calling qdisc_tree_reduce_backlog in peek after the qlen is restored.

[1] http://lore.kernel.org/netdev/CAN2cbVe79oj0O9==m4+4x3v+O+qzRagA=2=wkrp9i9=CqYvyZA@mail.gmail.com/

CVSS v3
9.8
EG Score
9.8(high)
EG Risk
49(Track)
EG Risk 49/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation1% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
42%
KEV
Not listed

Published

August 28, 2026

Last Modified

August 29, 2026

Advisory Details (8)

Auto-updated Aug 29, 2026
No patch confirmed yet.
generic

net/sched: sch_fq_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/af54df2f44d9605614bc7ed96640302a240a9a62
generic

net/sched: sch_fq_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/acc08a0c7f37ebb1901144e03a7cba7d4afd9203
generic

net/sched: sch_fq_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/94a5f1efdefb01f82cd228bf4e7ef1e8fc075c80
generic

net/sched: sch_fq_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/7c09843fd2b44d9bf0de798683861d1aecd62a08
generic

net/sched: sch_fq_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/3e515188393e62a718ccebee651ee74514104ff6
generic

net/sched: sch_fq_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/20dd591d8f951e1e6aca5052be8785e6181055e2
generic

net/sched: sch_fq_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/097f6fc7b1ae362dd7a9444b2572162fda73b284
generic

net/sched: sch_fq_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/0500af8630c3253f0dde879bd3a73a06bb2f2b3f

Vendor Advisories for CVE-2026-80630(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Data Freshness Timeline

(refreshed 18× in last 7d / 18× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-30 05:58 UTCGHSA enrichment
  2. 2026-08-30 02:13 UTCEG score recompute
  3. 2026-08-30 02:13 UTCGHSA enrichment
  4. 2026-08-30 01:22 UTCEPSS rescore
  5. 2026-08-29 22:29 UTCGHSA enrichment
  6. 2026-08-29 18:44 UTCGHSA enrichment
  7. 2026-08-29 14:59 UTCGHSA enrichment
  8. 2026-08-29 11:15 UTCEG score recompute
  9. 2026-08-29 11:14 UTCGHSA enrichment
  10. 2026-08-29 07:27 UTCEG score recompute
  11. 2026-08-29 07:27 UTCGHSA enrichment
  12. 2026-08-29 06:36 UTCEG score recompute▲ 9.80
  13. 2026-08-29 06:36 UTCGHSA enrichment
  14. 2026-08-29 06:33 UTCMITRE cvelistV5CVSS v3 → 9.8 · severity → CRITICAL
  15. 2026-08-28 21:42 UTCEPSS rescore
  16. 2026-08-28 08:20 UTCNVD update
  17. 2026-08-28 07:34 UTCEG score recompute
  18. 2026-08-28 07:32 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-80630?
CVE-2026-80630 is a critical vulnerability published on August 28, 2026. In the Linux kernel, the following vulnerability has been resolved: net/sched: schfqcodel: Do not call qdisctreereduce_backlog during peek before restoring qlen Whenever fq_codel drops packets during peek, it calls qdisctreereduce_backlog. An issue arises because it calls qdisctreereduce_backlog…
When was CVE-2026-80630 disclosed?
CVE-2026-80630 was first published in the National Vulnerability Database on August 28, 2026, with the most recent update on August 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-80630 actively exploited?
CVE-2026-80630 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 58.0% of all scored CVEs.
What is the CVSS score of CVE-2026-80630?
CVE-2026-80630 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-80630?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-80630, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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