{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-53221: ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup()","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-53221","status":"final","version":"1","initial_release_date":"2026-06-25T08:39:23.177Z","current_release_date":"2026-06-28T06:40:33.070Z","revision_history":[{"date":"2026-06-25T08:39:23.177Z","number":"1","summary":"Initial machine-readable export from HarborGuard."}]},"distribution":{"tlp":{"label":"WHITE"},"text":"Public CVE data; freely redistributable."},"notes":[{"category":"description","text":"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.","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-53221 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-53221"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-53221"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/c327fa4fca31415431202e063767a7ae342e19c6"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/fc657ac0767c49839b3ef0b08dc0953ca30883f8"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/47fb3c2b4203556308e64354b3e78f2ce221d646"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/f513f308cc4bdb4530d033431592ffbc29b7fca1"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/90fd4513315ca07da99cfd8549d3e553a7160f0d"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/2abfb19bbb81958714ad1d43ebeb65b30394184b"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/2fc7bc087cc7085368263d9d37bfe9a0bddd6a2d"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/a5c0359f5cbc51a2e2b114d6041e0f3c73f903e9"}]},"product_tree":{"branches":[{"category":"vendor","name":"Linux","branches":[{"category":"product_name","name":"Linux","branches":[{"category":"product_version_range","name":">=fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 <c327fa4fca31415431202e063767a7ae342e19c6","product":{"name":"Linux Linux >=fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 <c327fa4fca31415431202e063767a7ae342e19c6","product_id":"CSAFPID-1","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*"}}},{"category":"product_version_range","name":">=fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 <fc657ac0767c49839b3ef0b08dc0953ca30883f8","product":{"name":"Linux Linux >=fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 <fc657ac0767c49839b3ef0b08dc0953ca30883f8","product_id":"CSAFPID-2","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*"}}},{"category":"product_version_range","name":">=fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 <47fb3c2b4203556308e64354b3e78f2ce221d646","product":{"name":"Linux Linux >=fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 <47fb3c2b4203556308e64354b3e78f2ce221d646","product_id":"CSAFPID-3","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*"}}},{"category":"product_version_range","name":">=fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 <f513f308cc4bdb4530d033431592ffbc29b7fca1","product":{"name":"Linux Linux >=fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 <f513f308cc4bdb4530d033431592ffbc29b7fca1","product_id":"CSAFPID-4","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*"}}},{"category":"product_version_range","name":">=fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 <90fd4513315ca07da99cfd8549d3e553a7160f0d","product":{"name":"Linux Linux >=fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 <90fd4513315ca07da99cfd8549d3e553a7160f0d","product_id":"CSAFPID-5","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*"}}},{"category":"product_version_range","name":">=fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 <2abfb19bbb81958714ad1d43ebeb65b30394184b","product":{"name":"Linux Linux >=fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 <2abfb19bbb81958714ad1d43ebeb65b30394184b","product_id":"CSAFPID-6","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*"}}},{"category":"product_version_range","name":">=fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 <2fc7bc087cc7085368263d9d37bfe9a0bddd6a2d","product":{"name":"Linux Linux >=fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 <2fc7bc087cc7085368263d9d37bfe9a0bddd6a2d","product_id":"CSAFPID-7","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*"}}},{"category":"product_version_range","name":">=fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 <a5c0359f5cbc51a2e2b114d6041e0f3c73f903e9","product":{"name":"Linux Linux >=fbe68ee87522f6eaa10f9076c0a7117e1613f2f7 <a5c0359f5cbc51a2e2b114d6041e0f3c73f903e9","product_id":"CSAFPID-8","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*"}}}]}]},{"category":"vendor","name":"Linux","branches":[{"category":"product_name","name":"Linux","branches":[{"category":"product_version","name":"3.19","product":{"name":"Linux Linux 3.19","product_id":"CSAFPID-9","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:3.19:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"0","product":{"name":"Linux Linux 0","product_id":"CSAFPID-10","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:3.19:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"5.10.259","product":{"name":"Linux Linux 5.10.259","product_id":"CSAFPID-11","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:3.19:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"5.15.210","product":{"name":"Linux Linux 5.15.210","product_id":"CSAFPID-12","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:3.19:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"6.1.176","product":{"name":"Linux Linux 6.1.176","product_id":"CSAFPID-13","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:3.19:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"6.6.143","product":{"name":"Linux Linux 6.6.143","product_id":"CSAFPID-14","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:3.19:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"6.12.94","product":{"name":"Linux Linux 6.12.94","product_id":"CSAFPID-15","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:3.19:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"6.18.36","product":{"name":"Linux Linux 6.18.36","product_id":"CSAFPID-16","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:3.19:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"7.0.13","product":{"name":"Linux Linux 7.0.13","product_id":"CSAFPID-17","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:3.19:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"7.1","product":{"name":"Linux Linux 7.1","product_id":"CSAFPID-18","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:3.19:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-53221","title":"ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup()","notes":[{"category":"description","text":"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.","title":"CVE description"}],"product_status":{"known_affected":["CSAFPID-1","CSAFPID-2","CSAFPID-3","CSAFPID-4","CSAFPID-5","CSAFPID-6","CSAFPID-7","CSAFPID-8","CSAFPID-9"],"fixed":["CSAFPID-10","CSAFPID-11","CSAFPID-12","CSAFPID-13","CSAFPID-14","CSAFPID-15","CSAFPID-16","CSAFPID-17","CSAFPID-18"]},"scores":[{"cvss_v3":{"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"},"products":["CSAFPID-1","CSAFPID-2","CSAFPID-3","CSAFPID-4","CSAFPID-5","CSAFPID-6","CSAFPID-7","CSAFPID-8","CSAFPID-9"]}],"remediations":[{"category":"vendor_fix","details":"Update to a fixed version: 0, 2abfb19bbb81958714ad1d43ebeb65b30394184b, 2fc7bc087cc7085368263d9d37bfe9a0bddd6a2d, 47fb3c2b4203556308e64354b3e78f2ce221d646, 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, 6.18.36, 7.0.13, 7.1, 90fd4513315ca07da99cfd8549d3e553a7160f0d, a5c0359f5cbc51a2e2b114d6041e0f3c73f903e9, c327fa4fca31415431202e063767a7ae342e19c6, f513f308cc4bdb4530d033431592ffbc29b7fca1, fc657ac0767c49839b3ef0b08dc0953ca30883f8.","product_ids":["CSAFPID-1","CSAFPID-2","CSAFPID-3","CSAFPID-4","CSAFPID-5","CSAFPID-6","CSAFPID-7","CSAFPID-8","CSAFPID-9"]}]}]}