{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53221","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-06-09T07:44:35.392Z","datePublished":"2026-06-25T08:39:23.177Z","dateUpdated":"2026-08-05T12:34:14.672Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:34:14.672Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup()\n\nIn vti6_tnl_lookup(), when an exact match for a tunnel fails,\nthe code falls back to searching for wildcard tunnels:\n\n- Tunnels matching the packet's local address, with any remote address\n  wildcard remote).\n\n- Tunnels matching the packet's remote address, with any local address\n  (wildcard local).\n\nHowever, vti6 stores all these different types of tunnels in the same\nhash table (ip6n->tnls_r_l) prone to hash collisions.\n\nThe bug is that the fallback search loops in vti6_tnl_lookup() were\nmissing checks to ensure that the candidate tunnel actually has\na wildcard address."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - The vulnerable lookup is reached from IPv6 packet input through registered XFRM ESP/AH/IPComp and IP-in-IPv6 tunnel handlers, so a remote peer can trigger it with network traffic.\nAC:L - The bug is a deterministic missing wildcard-address check in a small hash table; once a plausible VTI6 configuration with colliding wildcard/exact tunnel entries exists, chosen packets reliably exercise the wrong lookup.\nPR:N - The packet receive path reaches `vti6_tnl_lookup()` before any per-packet authentication succeeds, and no local privilege is needed to send the triggering IPv6 traffic.\nUI:N - No victim user action is required; packets are processed by the kernel networking receive path.\nS:U - The impact remains within the kernel/networking security authority and does not by itself cross a VM, IOMMU, or host boundary.\nC:H - Wrong tunnel selection can associate decapsulated traffic with another VTI device, mark, and policy context; in a multi-tenant IPsec/VTI gateway this can expose tunneled plaintext across tunnel boundaries.\nI:H - The same confusion can deliver attacker-controlled inner packets under the wrong tunnel interface and policy context, enabling unauthorized modification or injection of traffic in the affected tunnel domain.\nA:H - Incorrect matching can consistently drop or misprocess traffic for affected tunnels, allowing loss of availability of the VTI/IPsec connectivity in vulnerable configurations."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv6/ip6_vti.c"],"versions":[{"version":"fbe68ee87522f6eaa10f9076c0a7117e1613f2f7","lessThan":"c327fa4fca31415431202e063767a7ae342e19c6","status":"affected","versionType":"git"},{"version":"fbe68ee87522f6eaa10f9076c0a7117e1613f2f7","lessThan":"fc657ac0767c49839b3ef0b08dc0953ca30883f8","status":"affected","versionType":"git"},{"version":"fbe68ee87522f6eaa10f9076c0a7117e1613f2f7","lessThan":"47fb3c2b4203556308e64354b3e78f2ce221d646","status":"affected","versionType":"git"},{"version":"fbe68ee87522f6eaa10f9076c0a7117e1613f2f7","lessThan":"f513f308cc4bdb4530d033431592ffbc29b7fca1","status":"affected","versionType":"git"},{"version":"fbe68ee87522f6eaa10f9076c0a7117e1613f2f7","lessThan":"90fd4513315ca07da99cfd8549d3e553a7160f0d","status":"affected","versionType":"git"},{"version":"fbe68ee87522f6eaa10f9076c0a7117e1613f2f7","lessThan":"2abfb19bbb81958714ad1d43ebeb65b30394184b","status":"affected","versionType":"git"},{"version":"fbe68ee87522f6eaa10f9076c0a7117e1613f2f7","lessThan":"2fc7bc087cc7085368263d9d37bfe9a0bddd6a2d","status":"affected","versionType":"git"},{"version":"fbe68ee87522f6eaa10f9076c0a7117e1613f2f7","lessThan":"a5c0359f5cbc51a2e2b114d6041e0f3c73f903e9","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv6/ip6_vti.c"],"versions":[{"version":"3.19","status":"affected"},{"version":"0","lessThan":"3.19","status":"unaffected","versionType":"semver"},{"version":"5.10.259","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.210","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.176","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.143","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.94","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.36","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.0.13","lessThanOrEqual":"7.0.*","status":"unaffected","versionType":"semver"},{"version":"7.1","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.19","versionEndExcluding":"5.10.259"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.19","versionEndExcluding":"5.15.210"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.19","versionEndExcluding":"6.1.176"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.19","versionEndExcluding":"6.6.143"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.19","versionEndExcluding":"6.12.94"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.19","versionEndExcluding":"6.18.36"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.19","versionEndExcluding":"7.0.13"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.19","versionEndExcluding":"7.1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/c327fa4fca31415431202e063767a7ae342e19c6"},{"url":"https://git.kernel.org/stable/c/fc657ac0767c49839b3ef0b08dc0953ca30883f8"},{"url":"https://git.kernel.org/stable/c/47fb3c2b4203556308e64354b3e78f2ce221d646"},{"url":"https://git.kernel.org/stable/c/f513f308cc4bdb4530d033431592ffbc29b7fca1"},{"url":"https://git.kernel.org/stable/c/90fd4513315ca07da99cfd8549d3e553a7160f0d"},{"url":"https://git.kernel.org/stable/c/2abfb19bbb81958714ad1d43ebeb65b30394184b"},{"url":"https://git.kernel.org/stable/c/2fc7bc087cc7085368263d9d37bfe9a0bddd6a2d"},{"url":"https://git.kernel.org/stable/c/a5c0359f5cbc51a2e2b114d6041e0f3c73f903e9"}],"title":"ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup()","x_generator":{"engine":"bippy-1.2.0"}}}}