CVE-2026-31684

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-04-25. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.5Exploit: NoneExposed: 0

A fix is available — apply it.

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

net: sched: act_csum: validate nested VLAN headers

tcf_csum_act() walks nested VLAN headers directly from skb->data when an skb still carries in-payload VLAN tags. The current code reads vlan->h_vlan_encapsulated_proto and then pulls VLAN_HLEN bytes without first ensuring that the full VLAN header is present in the linear area.

If only part of an inner VLAN header is linearized, accessing h_vlan_encapsulated_proto reads past the linear area, and the following skb_pull(VLAN_HLEN) may violate skb invariants.

Fix this by requiring pskb_may_pull(skb, VLAN_HLEN) before accessing and pulling each nested VLAN header. If the header still is not fully available, drop the packet through the existing error path.

CVSS v3
5.5
EG Score
5.5(medium)
EPSS
2.0%
KEV
Not listed

Published

April 25, 2026

Last Modified

June 1, 2026

Advisory Details (5)

Auto-updated May 6, 2026
No patch confirmed yet.
generic

net: sched: act_csum: validate nested VLAN headers - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/ec4930979b3f7bbeb7af5744599fc6603a4dba62
generic

net: sched: act_csum: validate nested VLAN headers - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/eb3765b90eb8f2a3d6310a80c14a9e57ec4267a2
generic

net: sched: act_csum: validate nested VLAN headers - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c842743d073bdd683606cb414eb0ca84465dd834
generic

net: sched: act_csum: validate nested VLAN headers - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/a69738efea0996d05a3c7d2178551b891744df1b
generic

net: sched: act_csum: validate nested VLAN headers - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/3d165d975305cf76ff0b10a3c798fb31e5f5f9a5

Vendor Advisories for CVE-2026-31684(10)

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

Patch Availability(5)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatkernel-0:6.12.0-211.18.1.el10_22026-05-28redhat
redhatkernel-rt-0:4.18.0-553.126.1.rt7.467.el8_102026-05-28redhat
redhatkernel-0:4.18.0-553.126.1.el8_102026-05-28redhat
redhatkernel-0:5.14.0-687.12.1.el9_82026-05-28redhat
linuxKernel @ 5.10.258—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.

Data Freshness Timeline

(refreshed 15× in last 7d / 36× 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 123 total refreshes for this CVE.

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

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Frequently asked(5)

What is CVE-2026-31684?
CVE-2026-31684 is a medium vulnerability published on April 25, 2026. In the Linux kernel, the following vulnerability has been resolved: net: sched: act_csum: validate nested VLAN headers tcfcsumact() walks nested VLAN headers directly from skb->data when an skb still carries in-payload VLAN tags. The current code reads vlan->hvlanencapsulatedproto and then pulls…
When was CVE-2026-31684 disclosed?
CVE-2026-31684 was first published in the National Vulnerability Database on April 25, 2026, with the most recent update on June 1, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-31684 actively exploited?
CVE-2026-31684 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-31684?
CVE-2026-31684 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-31684?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-31684, 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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