CVE-2026-53221

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-06-25. the CNA's CVSS baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:linux, epss, ghsa
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

A fix is available — apply it.

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

ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup()

In vti6_tnl_lookup(), when an exact match for a tunnel fails, the code falls back to searching for wildcard tunnels:

  • Tunnels matching the packet's local address, with any remote address
wildcard remote).
  • Tunnels matching the packet's remote address, with any local address
(wildcard local).

However, vti6 stores all these different types of tunnels in the same hash table (ip6n->tnls_r_l) prone to hash collisions.

The bug is that the fallback search loops in vti6_tnl_lookup() were missing checks to ensure that the candidate tunnel actually has a wildcard address.

CVSS v3
9.8
EG Score
9.8(medium)
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

June 25, 2026

Last Modified

August 5, 2026

Advisory Details (8)

Auto-updated Sep 9, 2026
No patch confirmed yet.
generic

ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/a5c0359f5cbc51a2e2b114d6041e0f3c73f903e9
generic

ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/2fc7bc087cc7085368263d9d37bfe9a0bddd6a2d
generic

ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/2abfb19bbb81958714ad1d43ebeb65b30394184b
generic

ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/90fd4513315ca07da99cfd8549d3e553a7160f0d
generic

ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/f513f308cc4bdb4530d033431592ffbc29b7fca1
generic

ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/47fb3c2b4203556308e64354b3e78f2ce221d646
generic

ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/fc657ac0767c49839b3ef0b08dc0953ca30883f8
generic

ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c327fa4fca31415431202e063767a7ae342e19c6

Vendor Advisories for CVE-2026-53221(2)

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

Patch Availability(7)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-virtual-hwe-26.04-edge (7.0.0-29.29) @ resolute2026-08-30ubuntu
ubuntulinux-tools-nvidia-hwe-24.04-edge (7.0.0-1016.16~24.04.1) @ noble2026-08-30ubuntu
ubuntulinux-tools-gke-hwe-26.04 (7.0.0-1005.6) @ resolute2026-08-30ubuntu
ubuntulinux-virtual-hwe-24.04-edge (7.0.0-29.29~24.04.2) @ noble2026-08-30ubuntu
ubuntulinux-tools-aws-edge (7.0.0-1010.10~24.04.1) @ noble2026-08-30ubuntu
ubuntulinux-tools-oem-7.0 (7.0.0-1010.10) @ resolute2026-08-30ubuntu
ubuntulinux-tools-nvidia-hwe-26.04 (7.0.0-2016.16) @ resolute2026-08-30ubuntu

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 ... 6.12.94-1~bpo12+1 (27 versions)6.12.94-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 7.0.9-1~bpo13+1 (145 versions)7.0.13-1—

Additional Vendor Advisories

(7)

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 / 159× 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 621 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-53221?
CVE-2026-53221 is a critical vulnerability published on June 25, 2026. In the Linux kernel, the following vulnerability has been resolved: ip6vti: fix incorrect tunnel matching in vti6tnl_lookup() In vti6tnllookup(), when an exact match for a tunnel fails, the code falls back to searching for wildcard tunnels: Tunnels matching the packet's local address, with any…
When was CVE-2026-53221 disclosed?
CVE-2026-53221 was first published in the National Vulnerability Database on June 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-2026-53221 actively exploited?
CVE-2026-53221 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 57.8% of all scored CVEs.
What is the CVSS score of CVE-2026-53221?
CVE-2026-53221 has a CVSS v4.0 base score of 9.8 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-53221?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-53221, 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-2026-53221

Explore →

Is Your Infrastructure Affected by CVE-2026-53221?

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

Start Free Scan →Browse All CVEs