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
5.5EG
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: 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)
EG Risk
29(Track)
EG Risk 29/100SSVC: 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%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
2%
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(16)

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

Patch Availability(15)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatkernel-0:4.18.0-305.199.1.el8_42026-07-30redhat
redhatkernel-rt-0:5.14.0-284.183.1.rt14.468.el9_22026-07-30redhat
redhatkernel-0:4.18.0-477.156.1.el8_82026-07-29redhat
redhatkernel-0:5.14.0-284.183.1.el9_22026-07-29redhat
redhatkernel-0:6.12.0-55.92.1.el10_02026-07-23redhat
redhatkernel-0:5.14.0-570.129.1.el9_62026-07-23redhat
redhatkernel-0:5.14.0-427.139.1.el9_42026-07-22redhat
redhatkernel-0:3.10.0-1160.156.1.el72026-07-17redhat
redhatkernel-rt-0:3.10.0-1160.156.1.rt56.1308.el72026-07-17redhat
redhatkernel-0:4.18.0-372.201.1.el8_62026-07-15redhat
redhatkernel-0:5.14.0-687.12.1.el9_82026-05-28redhat
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
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.

Affected Packages

(5 across 4 ecosystems)
Debian:11(2)
PackageVulnerable rangeFixed inDependents
linux5.10.103-1 ... 5.10.92-2 (54 versions)5.10.259-1—
linux-6.16.1.106-3~deb11u1 ... 6.1.174-1~deb11u1 (20 versions)6.1.176-1~deb11u1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux6.1.106-1 ... 6.1.99-1 (53 versions)6.1.176-1—
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 (126 versions)6.19.14-1—

Additional Vendor Advisories

(10)

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 188 total refreshes for this CVE.

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

Related CVEs(same product + same vendor)

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 0% probability of exploitation in the next 30 days, which ranks it in the top 98.2% of all scored CVEs.
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.

Dependency Blast Radius

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