CVE-2026-22976

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-01-21. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: None knownExposed: 0

A fix is available — apply it.

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

net/sched: sch_qfq: Fix NULL deref when deactivating inactive aggregate in qfq_reset

qfq_class->leaf_qdisc->q.qlen > 0 does not imply that the class itself is active.

Two qfq_class objects may point to the same leaf_qdisc. This happens when:

  • one QFQ qdisc is attached to the dev as the root qdisc, and
  • another QFQ qdisc is temporarily referenced (e.g., via qdisc_get()
/ qdisc_put()) and is pending to be destroyed, as in function tc_new_tfilter.

When packets are enqueued through the root QFQ qdisc, the shared leaf_qdisc->q.qlen increases. At the same time, the second QFQ qdisc triggers qdisc_put and qdisc_destroy: the qdisc enters qfq_reset() with its own q->q.qlen == 0, but its class's leaf qdisc->q.qlen > 0. Therefore, the qfq_reset would wrongly deactivate an inactive aggregate and trigger a null-deref in qfq_deactivate_agg:

[ 0.903172] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 0.903571] #PF: supervisor write access in kernel mode [ 0.903860] #PF: error_code(0x0002) - not-present page [ 0.904177] PGD 10299b067 P4D 10299b067 PUD 10299c067 PMD 0 [ 0.904502] Oops: Oops: 0002 [#1] SMP NOPTI [ 0.904737] CPU: 0 UID: 0 PID: 135 Comm: exploit Not tainted 6.19.0-rc3+ #2 NONE [ 0.905157] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 [ 0.905754] RIP: 0010:qfq_deactivate_agg (include/linux/list.h:992 (discriminator 2) include/linux/list.h:1006 (discriminator 2) net/sched/sch_qfq.c:1367 (discriminator 2) net/sched/sch_qfq.c:1393 (discriminator 2)) [ 0.906046] Code: 0f 84 4d 01 00 00 48 89 70 18 8b 4b 10 48 c7 c2 ff ff ff ff 48 8b 78 08 48 d3 e2 48 21 f2 48 2b 13 48 8b 30 48 d3 ea 8b 4b 18 0

Code starting with the faulting instruction =========================================== 0: 0f 84 4d 01 00 00 je 0x153 6: 48 89 70 18 mov %rsi,0x18(%rax) a: 8b 4b 10 mov 0x10(%rbx),%ecx d: 48 c7 c2 ff ff ff ff mov $0xffffffffffffffff,%rdx 14: 48 8b 78 08 mov 0x8(%rax),%rdi 18: 48 d3 e2 shl %cl,%rdx 1b: 48 21 f2 and %rsi,%rdx 1e: 48 2b 13 sub (%rbx),%rdx 21: 48 8b 30 mov (%rax),%rsi 24: 48 d3 ea shr %cl,%rdx 27: 8b 4b 18 mov 0x18(%rbx),%ecx ... [ 0.907095] RSP: 0018:ffffc900004a39a0 EFLAGS: 00010246 [ 0.907368] RAX: ffff8881043a0880 RBX: ffff888102953340 RCX: 0000000000000000 [ 0.907723] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [ 0.908100] RBP: ffff888102952180 R08: 0000000000000000 R09: 0000000000000000 [ 0.908451] R10: ffff8881043a0000 R11: 0000000000000000 R12: ffff888102952000 [ 0.908804] R13: ffff888102952180 R14: ffff8881043a0ad8 R15: ffff8881043a0880 [ 0.909179] FS: 000000002a1a0380(0000) GS:ffff888196d8d000(0000) knlGS:0000000000000000 [ 0.909572] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 0.909857] CR2: 0000000000000000 CR3: 0000000102993002 CR4: 0000000000772ef0 [ 0.910247] PKRU: 55555554 [ 0.910391] Call Trace: [ 0.910527] [ 0.910638] qfq_reset_qdisc (net/sched/sch_qfq.c:357 net/sched/sch_qfq.c:1485) [ 0.910826] qdisc_reset (include/linux/skbuff.h:2195 include/linux/skbuff.h:2501 include/linux/skbuff.h:3424 include/linux/skbuff.h:3430 net/sched/sch_generic.c:1036) [ 0.911040] __qdisc_destroy (net/sched/sch_generic.c:1076) [ 0.911236] tc_new_tfilter (net/sched/cls_api.c:2447) [ 0.911447] rtnetlink_rcv_msg (net/core/rtnetlink.c:6958) [ 0.911663] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6861) [ 0.911894] netlink_rcv_skb (net/netlink/af_netlink.c:2550) [ 0.912100] netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344) [ 0.912296] ? __alloc_skb (net/core/skbuff.c:706) [ 0.912484] netlink_sendmsg (net/netlink/af ---truncated---

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
25(Track)
EG Risk 25/100SSVC: 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
Severity55% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
4%
KEV
Not listed

Published

January 21, 2026

Last Modified

June 17, 2026

Advisory Details (8)

Auto-updated Aug 8, 2026
No patch confirmed yet.
generic

SSA-253495

https://cert-portal.siemens.com/productcert/html/ssa-253495.html
generic

net/sched: sch_qfq: Fix NULL deref when deactivating inactive aggregate in qfq_reset - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/cdb24200b043438a144df501f1ebbd926bb1a2c7
generic

net/sched: sch_qfq: Fix NULL deref when deactivating inactive aggregate in qfq_reset - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c1d73b1480235731e35c81df70b08f4714a7d095
generic

net/sched: sch_qfq: Fix NULL deref when deactivating inactive aggregate in qfq_reset - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/6116a83ec167d3ab1390cded854d237481f41b63
generic

net/sched: sch_qfq: Fix NULL deref when deactivating inactive aggregate in qfq_reset - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/51ffd447bc37bf1a5776b85523f51d2bc69977f6
generic

net/sched: sch_qfq: Fix NULL deref when deactivating inactive aggregate in qfq_reset - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/43497313d0da3e12b5cfcd97aa17bf48ee663f95
generic

net/sched: sch_qfq: Fix NULL deref when deactivating inactive aggregate in qfq_reset - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/11bf9134613f6c71fc0ff36c5d8d33856f6ae3bb
generic

net/sched: sch_qfq: Fix NULL deref when deactivating inactive aggregate in qfq_reset - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/0809c4bc06c9c961222df29f2eccfd449304056f

Vendor Advisories for CVE-2026-22976(2)

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

Patch Availability(17)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-xilinx-zynqmp-tools-5.15.0-1067 (5.15.0-1067.71) @ jammy2026-05-29ubuntu
ubuntulinux-tools-gcp-fips-5.15 (5.15.0.1103.93) @ jammy2026-05-29ubuntu
ubuntulinux-tools-gke-5.15 (5.15.0.1099.98) @ jammy2026-05-29ubuntu
ubuntulinux-tools-realtime-5.15 (5.15.0.1102.106) @ jammy2026-05-29ubuntu
ubuntulinux-tools-azure-edge (5.15.0.1110.119~20.04.1) @ focal2026-05-29ubuntu
ubuntulinux-tools-azure-lts-22.04 (5.15.0.1109.107) @ jammy2026-05-29ubuntu
ubuntulinux-tools-nvidia-tegra-igx-rt-5.15 (5.15.0.1044.46) @ jammy2026-05-29ubuntu
ubuntulinux-tools-azure-fips-5.15 (5.15.0.1109.94) @ jammy2026-05-29ubuntu
ubuntulinux-tools-intel-iot-realtime-5.15 (5.15.0.1094.98) @ jammy2026-05-29ubuntu
ubuntulinux-tools-raspi-nolpae (5.15.0.1097.95) @ jammy2026-05-29ubuntu
ubuntulinux-virtual-6.8 (6.8.0-117.117) @ noble2026-05-29ubuntu
ubuntulinux-tools-azure-lts-24.04 (6.8.0-1056.62) @ noble2026-05-29ubuntu
ubuntulinux-tools-nvidia-tegra-rt-6.8 (6.8.0-1024.24) @ noble2026-05-29ubuntu
ubuntulinux-tools-nvidia-lowlatency-64k-6.8 (6.8.0-1054.57.1) @ noble2026-05-29ubuntu
ubuntulinux-tools-nvidia-hwe-22.04-edge (6.8.0-1054.57~22.04.1) @ jammy2026-05-29ubuntu
ubuntulinux-tools-fips-6.8 (6.8.0-116.116+fips1) @ noble2026-05-29ubuntu
linuxKernel @ 5.10.248—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 ... 5.10.92-2 (48 versions)5.10.249-1—
linux-6.16.1.106-3~deb11u1 ... 6.1.159-1~deb11u1 (14 versions)6.1.162-1~deb11u1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux6.1.106-1 ... 6.1.99-1 (46 versions)6.1.162-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux6.12.38-1 ... 6.12.69-1~bpo12+1 (10 versions)6.12.69-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 6.18~rc7-1~exp1 (96 versions)6.18.8-1—

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 5× in last 7d / 22× 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 158 total refreshes for this CVE.

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

Related CVEs

Related CVEs are temporarily unavailable — the same-product, same-vendor and same-CWE lists could not be loaded just now. That is not a sign that none exist; please retry shortly.

Frequently asked(5)

What is CVE-2026-22976?
CVE-2026-22976 is a medium vulnerability published on January 21, 2026. In the Linux kernel, the following vulnerability has been resolved: net/sched: schqfq: Fix NULL deref when deactivating inactive aggregate in qfqreset qfqclass->leafqdisc->q.qlen > 0 does not imply that the class itself is active. Two qfqclass objects may point to the same leafqdisc. This happens…
When was CVE-2026-22976 disclosed?
CVE-2026-22976 was first published in the National Vulnerability Database on January 21, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-22976 actively exploited?
CVE-2026-22976 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 96.4% of all scored CVEs.
What is the CVSS score of CVE-2026-22976?
CVE-2026-22976 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-22976?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-22976, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-22976

Explore →

Is Your Infrastructure Affected by CVE-2026-22976?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs