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Vulnerabilities

Vulnerability · CVE-2026-53221

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 tunn

Published Jun 25, 2026 · catalog updated Oct 17, 2026 · Canonical Ubuntu

Check if you run it

No confirmed exploitation is on record for CVE-2026-53221. EPSS is 0.58%. Act only if a listed version of Canonical Ubuntu is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Critical9.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.58%
Remediation
Advisory link
Affected products
Ubuntu:16.04:LTS linux-hwe-edge · Ubuntu:Pro:14.04:LTS linux-aws · Ubuntu:Pro:14.04:LTS linux-azure · Ubuntu:Pro:14.04:LTS linux-lts-xenial · Ubuntu:Pro:16.04:LTS linux · Ubuntu:Pro:16.04:LTS linux-aws

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Ubuntu:16.04:LTS linux-hwe-edge4.8.0-28.30~16.04.1, 4.8.0-30.32~16.04.1, 4.8.0-32.34~16.04.1
  • Ubuntu:Pro:14.04:LTS linux-aws0 → 4.4.0-1159.165
  • Ubuntu:Pro:14.04:LTS linux-azure0 → 4.15.0-1207.222~14.04.1
  • Ubuntu:Pro:14.04:LTS linux-lts-xenial0 → 4.4.0-288.322~14.04.1
  • Ubuntu:Pro:16.04:LTS linux0 → 4.4.0-288.322
  • Ubuntu:Pro:16.04:LTS linux-aws0 → 4.4.0-1197.212
  • Ubuntu:Pro:16.04:LTS linux-aws-hwe0 → 4.15.0-1197.210~16.04.1
  • Ubuntu:Pro:16.04:LTS linux-azure0 → 4.15.0-1208.223~16.04.1
  • Ubuntu:Pro:16.04:LTS linux-gcp0 → 4.15.0-1190.207~16.04.1
  • Ubuntu:Pro:16.04:LTS linux-hwe0 → 4.15.0-260.272~16.04.2
  • Ubuntu:Pro:16.04:LTS linux-kvm0 → 4.4.0-1160.171
  • Ubuntu:Pro:16.04:LTS linux-oracle0 → 4.15.0-1160.171~16.04.1
  • cpe linux/linux kernel7.1

How to fix CVE-2026-53221

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-53221. EPSS is 0.58%. Act only if a listed version of Canonical Ubuntu is installed.

Which versions are affected?

Compare what you have installed with linux/linux kernel 7.1. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.58%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Ubuntu security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 25, 2026 · NIST NVD

    Detected

    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 add

  2. Oct 15, 2026 · NIST NVD

    Updated

    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 add

  3. Oct 17, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    linux-aws fixed in 4.4.0-1159.165; linux-azure fixed in 4.15.0-1207.222~14.04.1; linux-lts-xenial fixed in 4.4.0-288.322~14.04.1; linux fixed in 4.4.0-288.322

  4. Oct 17, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    linux-aws fixed in 4.4.0-1159.165

  5. Oct 17, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    linux-azure fixed in 4.15.0-1207.222~14.04.1

  6. Oct 17, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    linux-lts-xenial fixed in 4.4.0-288.322~14.04.1

  7. Oct 17, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    linux fixed in 4.4.0-288.322

  8. Oct 17, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    linux-aws fixed in 4.4.0-1197.212

  9. Oct 17, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    linux-aws-hwe fixed in 4.15.0-1197.210~16.04.1

  10. Oct 17, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    linux-azure fixed in 4.15.0-1208.223~16.04.1

  11. Oct 17, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    linux-gcp fixed in 4.15.0-1190.207~16.04.1

  12. Oct 17, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    linux-hwe fixed in 4.15.0-260.272~16.04.2

  13. Oct 17, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    linux-kvm fixed in 4.4.0-1160.171

  14. Oct 17, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    linux-oracle fixed in 4.15.0-1160.171~16.04.1

  15. Oct 17, 2026 · OpenSSF OSV / OSV Scanner

    Updated

    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 add

Sources

  • CVE.orgVulnerability recordCVE-2026-53221

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-53221

    30-day exploitation probability 0.6%

    first.org
  • NIST NVDVulnerability recordCVE-2026-53221

    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

    nvd.nist.gov
  • OpenSSF OSV / OSV ScannerPackage advisoryUBUNTU-CVE-2026-53221
    osv.dev
  • Ubuntu Security NoticesVendor advisoryCVE-2026-53221

    Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - S390 architecture; - IIO ADC drivers; - Multiple devices driver; - PCI subsystem; - VFIO drivers;

    ubuntu.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.