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Vulnerability record · CVE-2026-53221 · published 25 June 2026

CVE-2026-53221: Linux kernel vulnerability

Linux · Linux Kernel

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.

9.8 CVSS 3.1 Critical EPSS 0.76% · top 46.7%
9.8CVSS 3.1 base score
0.76%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
8References
2 Jul 2026Last modified by NVD

Description

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:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

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

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Source: NIST National Vulnerability Database (record CVE-2026-53221), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.