CVE-2026-23340

HIGHPre-NVD 7.87.8—
EchelonGraph scoreMEDIUM confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-03-25. the CNA's CVSS baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:linux, epss, ghsa
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.8Exploit: 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: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs

When shrinking the number of real tx queues, netif_set_real_num_tx_queues() calls qdisc_reset_all_tx_gt() to flush qdiscs for queues which will no longer be used.

qdisc_reset_all_tx_gt() currently serializes qdisc_reset() with qdisc_lock(). However, for lockless qdiscs, the dequeue path is serialized by qdisc_run_begin/end() using qdisc->seqlock instead, so qdisc_reset() can run concurrently with __qdisc_run() and free skbs while they are still being dequeued, leading to UAF.

This can easily be reproduced on e.g. virtio-net by imposing heavy traffic while frequently changing the number of queue pairs:

iperf3 -ub0 -c $peer -t 0 & while :; do ethtool -L eth0 combined 1 ethtool -L eth0 combined 2 done

With KASAN enabled, this leads to reports like:

BUG: KASAN: slab-use-after-free in __qdisc_run+0x133f/0x1760 ... Call Trace: ... __qdisc_run+0x133f/0x1760 __dev_queue_xmit+0x248f/0x3550 ip_finish_output2+0xa42/0x2110 ip_output+0x1a7/0x410 ip_send_skb+0x2e6/0x480 udp_send_skb+0xb0a/0x1590 udp_sendmsg+0x13c9/0x1fc0 ...

Allocated by task 1270 on cpu 5 at 44.558414s: ... alloc_skb_with_frags+0x84/0x7c0 sock_alloc_send_pskb+0x69a/0x830 __ip_append_data+0x1b86/0x48c0 ip_make_skb+0x1e8/0x2b0 udp_sendmsg+0x13a6/0x1fc0 ...

Freed by task 1306 on cpu 3 at 44.558445s: ... kmem_cache_free+0x117/0x5e0 pfifo_fast_reset+0x14d/0x580 qdisc_reset+0x9e/0x5f0 netif_set_real_num_tx_queues+0x303/0x840 virtnet_set_channels+0x1bf/0x260 [virtio_net] ethnl_set_channels+0x684/0xae0 ethnl_default_set_doit+0x31a/0x890 ...

Serialize qdisc_reset_all_tx_gt() against the lockless dequeue path by taking qdisc->seqlock for TCQ_F_NOLOCK qdiscs, matching the serialization model already used by dev_reset_queue().

Additionally clear QDISC_STATE_NON_EMPTY after reset so the qdisc state reflects an empty queue, avoiding needless re-scheduling.

CVSS v3
7.8
EG Score
7.8(medium)
EG Risk
40(Track)
EG Risk 40/100SSVC: 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
Severity78% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
3%
KEV
Not listed

Published

March 25, 2026

Last Modified

August 5, 2026

Advisory Details (7)

Auto-updated Jun 10, 2026
No patch confirmed yet.
generic

net: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/dbd58b0730aa06ab6ad26079cf9a5b6b58e7e750
generic

net: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c69df4e0524f8de8e176ba389acd83e85f5f49d0
generic

net: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/8314944cc3bdeaa5a73e6f8a8cf0d94822e625cb
generic

net: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/7f083faf59d14c04e01ec05a7507f036c965acf8
generic

net: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/7594467c49bfc2f4644dee0415ac2290db11fa0d
generic

net: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/5bc4e69306ed7ae02232eb4c0b23ed621a26d504
generic

net: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/5bb27ad54d12de67e457d7d251198e361bef835e

Vendor Advisories for CVE-2026-23340(2)

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

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 5.15.203—osv
linuxKernel @ 6.1.167—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(5 across 4 ecosystems)
Debian:11(2)
PackageVulnerable rangeFixed inDependents
linux5.10.103-1 ... 7.2~rc5-1~exp1 (496 versions)——
linux-6.16.1.106-3~deb11u1 ... 6.1.164-1~deb11u1 (16 versions)6.1.170-1~deb11u1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux6.1.106-1 ... 6.1.99-1 (48 versions)6.1.170-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux6.12.38-1 ... 6.12.85-1~bpo12+1 (17 versions)6.12.85-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 6.19~rc8-1~exp1 (117 versions)6.19.8-1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(24)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 6× in last 7d / 57× 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.

Showing the most recent 100 of 215 total refreshes for this CVE.

  1. 2026-09-04 05:06 UTCEPSS rescore
  2. 2026-09-02 15:01 UTCOSV refresh
  3. 2026-09-01 13:53 UTCEPSS rescore
  4. 2026-09-01 04:39 UTCEPSS rescore
  5. 2026-08-30 19:17 UTCEPSS rescore
  6. 2026-08-30 01:22 UTCEPSS rescore
  7. 2026-08-28 21:41 UTCEPSS rescore
  8. 2026-08-27 14:25 UTCEPSS rescore
  9. 2026-08-26 14:46 UTCEPSS rescore
  10. 2026-08-25 13:48 UTCEPSS rescore
  11. 2026-08-23 00:19 UTCEPSS rescore
  12. 2026-08-21 23:49 UTCEPSS rescore
  13. 2026-08-20 22:55 UTCEPSS rescore
  14. 2026-08-19 17:03 UTCEPSS rescore
  15. 2026-08-18 13:48 UTCEPSS rescore
  16. 2026-08-17 13:47 UTCEPSS rescore
  17. 2026-08-16 14:56 UTCEPSS rescore
  18. 2026-08-16 10:24 UTCEG score recompute
  19. 2026-08-16 10:24 UTCVendor advisory
  20. 2026-08-16 10:24 UTCGHSA enrichment
  21. 2026-08-16 02:14 UTCEPSS rescore
  22. 2026-08-15 01:30 UTCEPSS rescore
  23. 2026-08-14 19:35 UTCVendor advisory
  24. 2026-08-14 19:35 UTCGHSA enrichment
  25. 2026-08-14 06:44 UTCEG score recompute
Show 75 more
  1. 2026-08-14 06:44 UTCVendor advisory
  2. 2026-08-14 06:44 UTCGHSA enrichment
  3. 2026-08-13 22:00 UTCEPSS rescore
  4. 2026-08-12 20:59 UTCEG score recompute
  5. 2026-08-12 20:59 UTCVendor advisory
  6. 2026-08-12 20:59 UTCGHSA enrichment
  7. 2026-08-12 13:50 UTCEPSS rescore
  8. 2026-08-11 21:01 UTCEG score recompute
  9. 2026-08-11 21:01 UTCVendor advisory
  10. 2026-08-11 21:01 UTCGHSA enrichment
  11. 2026-08-11 13:42 UTCEPSS rescore
  12. 2026-08-11 04:05 UTCEG score recompute
  13. 2026-08-11 04:05 UTCVendor advisory
  14. 2026-08-11 04:04 UTCGHSA enrichment
  15. 2026-08-11 00:00 UTCEPSS rescore
  16. 2026-08-10 06:58 UTCVendor advisory
  17. 2026-08-10 06:58 UTCGHSA enrichment
  18. 2026-08-09 18:39 UTCVendor advisory
  19. 2026-08-09 18:39 UTCGHSA enrichment
  20. 2026-08-09 06:19 UTCEG score recompute
  21. 2026-08-09 06:19 UTCVendor advisory
  22. 2026-08-09 06:19 UTCGHSA enrichment
  23. 2026-08-08 16:37 UTCEPSS rescore
  24. 2026-08-08 04:56 UTCVendor advisory
  25. 2026-08-08 04:56 UTCGHSA enrichment
  26. 2026-08-07 16:36 UTCEG score recompute
  27. 2026-08-07 16:36 UTCVendor advisory
  28. 2026-08-07 16:36 UTCGHSA enrichment
  29. 2026-08-06 19:01 UTCEG score recompute
  30. 2026-08-06 19:01 UTCVendor advisory
  31. 2026-08-06 19:01 UTCGHSA enrichment
  32. 2026-08-06 13:46 UTCEPSS rescore
  33. 2026-08-06 01:05 UTCEG score recompute
  34. 2026-08-06 01:05 UTCVendor advisory
  35. 2026-08-06 01:05 UTCGHSA enrichment
  36. 2026-08-05 19:17 UTCEPSS rescore
  37. 2026-08-05 12:43 UTCEG score recompute
  38. 2026-08-05 12:43 UTCVendor advisory
  39. 2026-08-05 12:43 UTCGHSA enrichment
  40. 2026-08-04 15:10 UTCEPSS rescore
  41. 2026-08-04 10:38 UTCEPSS rescore
  42. 2026-08-03 23:51 UTCEG score recompute
  43. 2026-08-03 23:51 UTCVendor advisory
  44. 2026-08-03 23:51 UTCGHSA enrichment
  45. 2026-08-03 10:35 UTCEPSS rescore
  46. 2026-08-02 15:38 UTCEG score recompute
  47. 2026-08-02 15:38 UTCVendor advisory
  48. 2026-08-02 15:38 UTCGHSA enrichment
  49. 2026-08-02 02:26 UTCEPSS rescore
  50. 2026-08-01 04:15 UTCEPSS rescore
  51. 2026-07-30 01:30 UTCEPSS rescore
  52. 2026-07-27 14:13 UTCEPSS rescore
  53. 2026-07-26 14:54 UTCEPSS rescore
  54. 2026-07-26 14:54 UTCEPSS rescore
  55. 2026-07-24 14:17 UTCEPSS rescore
  56. 2026-07-23 14:18 UTCEPSS rescore
  57. 2026-07-23 14:18 UTCEPSS rescore
  58. 2026-07-23 03:07 UTCEG score recompute
  59. 2026-07-22 14:08 UTCEPSS rescore
  60. 2026-07-21 15:24 UTCEPSS rescore
  61. 2026-07-21 15:24 UTCEPSS rescore
  62. 2026-07-20 17:08 UTCEPSS rescore
  63. 2026-07-19 14:31 UTCEPSS rescore
  64. 2026-07-19 14:31 UTCEPSS rescore
  65. 2026-07-19 02:29 UTCEPSS rescore
  66. 2026-07-19 02:28 UTCEPSS rescore
  67. 2026-07-18 10:04 UTCEPSS rescore
  68. 2026-07-18 10:04 UTCEPSS rescore
  69. 2026-07-17 07:16 UTCOSV refresh
  70. 2026-07-16 17:03 UTCEPSS rescore
  71. 2026-07-16 17:03 UTCEPSS rescore
  72. 2026-07-15 16:57 UTCEPSS rescore
  73. 2026-07-15 16:57 UTCEPSS rescore
  74. 2026-07-15 02:00 UTCEPSS rescore
  75. 2026-07-15 02:00 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-23340?
CVE-2026-23340 is a high vulnerability published on March 25, 2026. In the Linux kernel, the following vulnerability has been resolved: net: sched: avoid qdiscresetalltxgt() vs dequeue race for lockless qdiscs When shrinking the number of real tx queues, netifsetrealnumtxqueues() calls qdiscresetalltx_gt() to flush qdiscs for queues which will no longer be used.…
When was CVE-2026-23340 disclosed?
CVE-2026-23340 was first published in the National Vulnerability Database on March 25, 2026, with the most recent update on August 5, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-23340 actively exploited?
CVE-2026-23340 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 96.6% of all scored CVEs.
What is the CVSS score of CVE-2026-23340?
CVE-2026-23340 has a CVSS v4.0 base score of 7.8 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-23340?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-23340, 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.

Dependency Blast Radius

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