CRITICAL: CVE-2026-53221 (CVSS 9.8) — multiple products

CVE: CVE-2026-53221

CVSS: 9.8 (3.1) — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: CRITICAL

Status: Critical advisory

Affected

_See vendor advisory_

Summary

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.

Verified Sources

• NVD entry
• GitHub Advisory
• MITRE

References

• https://git.kernel.org/stable/c/2abfb19bbb81958714ad1d43ebeb65b30394184b
• https://git.kernel.org/stable/c/2fc7bc087cc7085368263d9d37bfe9a0bddd6a2d
• https://git.kernel.org/stable/c/47fb3c2b4203556308e64354b3e78f2ce221d646
• https://git.kernel.org/stable/c/90fd4513315ca07da99cfd8549d3e553a7160f0d
• https://git.kernel.org/stable/c/a5c0359f5cbc51a2e2b114d6041e0f3c73f903e9
• https://git.kernel.org/stable/c/c327fa4fca31415431202e063767a7ae342e19c6
• https://git.kernel.org/stable/c/f513f308cc4bdb4530d033431592ffbc29b7fca1
• https://git.kernel.org/stable/c/fc657ac0767c49839b3ef0b08dc0953ca30883f8

_Validated by the Lyrie Threat Intelligence Pipeline — 3 independent sources confirmed before publication. No speculation._