{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-53228: ipv6: sit: reload inner IPv6 header after GSO offloads","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-53228","status":"final","version":"1","initial_release_date":"2026-06-25T08:39:27.893Z","current_release_date":"2026-06-28T06:40:38.747Z","revision_history":[{"date":"2026-06-25T08:39:27.893Z","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\nipv6: sit: reload inner IPv6 header after GSO offloads\n\nipip6_tunnel_xmit() caches the inner IPv6 header pointer at function\nentry and continues using it after iptunnel_handle_offloads().\n\nFor GSO skbs, iptunnel_handle_offloads() calls skb_header_unclone().\nWhen the skb header is cloned, skb_header_unclone() can call\npskb_expand_head(), which may move the skb head. The pskb_expand_head()\ncontract requires pointers into the skb header to be reloaded after the\ncall.\n\nIf the later skb_realloc_headroom() branch is not taken, SIT uses the\nstale iph6 pointer to read the inner hop limit and DS field. That can\nread from a freed skb head after the old head's remaining clone is\nreleased.\n\nReload iph6 after the offload helper succeeds and before subsequent\nreads from the inner IPv6 header. Keep the existing reload after\nskb_realloc_headroom(), since that branch can also replace the skb.","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-53228 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-53228"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-53228"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/fddd41445a0537b093e6b3f6232c9933cad1e48b"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/1132e5edc2866c3530be17622153a597095f0e43"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/9c67b44edb3598d234efae6e44649eb993c03da5"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/0bfa7bba1f41aaf5f0604dc712bb4701493e3aa0"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/59f80c919713250fe5d25a4d9aea4e49580fa1d4"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/2fa49b2715e1bad12ce3b0fa64e234d9582c8193"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/cb658c2f5f7977c2a1c77c9f239f4bc8196edb5c"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/f0e42f0c4337b1f220de1ddd63f47197c7dee4de"}]},"product_tree":{"branches":[{"category":"vendor","name":"Linux","branches":[{"category":"product_name","name":"Linux","branches":[{"category":"product_version_range","name":">=14909664e4e192f4c6f6fcdccd9919af7cf783ab <fddd41445a0537b093e6b3f6232c9933cad1e48b","product":{"name":"Linux Linux >=14909664e4e192f4c6f6fcdccd9919af7cf783ab <fddd41445a0537b093e6b3f6232c9933cad1e48b","product_id":"CSAFPID-1","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*"}}},{"category":"product_version_range","name":">=14909664e4e192f4c6f6fcdccd9919af7cf783ab <1132e5edc2866c3530be17622153a597095f0e43","product":{"name":"Linux Linux >=14909664e4e192f4c6f6fcdccd9919af7cf783ab <1132e5edc2866c3530be17622153a597095f0e43","product_id":"CSAFPID-2","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*"}}},{"category":"product_version_range","name":">=14909664e4e192f4c6f6fcdccd9919af7cf783ab <9c67b44edb3598d234efae6e44649eb993c03da5","product":{"name":"Linux Linux >=14909664e4e192f4c6f6fcdccd9919af7cf783ab <9c67b44edb3598d234efae6e44649eb993c03da5","product_id":"CSAFPID-3","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*"}}},{"category":"product_version_range","name":">=14909664e4e192f4c6f6fcdccd9919af7cf783ab <0bfa7bba1f41aaf5f0604dc712bb4701493e3aa0","product":{"name":"Linux Linux >=14909664e4e192f4c6f6fcdccd9919af7cf783ab <0bfa7bba1f41aaf5f0604dc712bb4701493e3aa0","product_id":"CSAFPID-4","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*"}}},{"category":"product_version_range","name":">=14909664e4e192f4c6f6fcdccd9919af7cf783ab <59f80c919713250fe5d25a4d9aea4e49580fa1d4","product":{"name":"Linux Linux >=14909664e4e192f4c6f6fcdccd9919af7cf783ab <59f80c919713250fe5d25a4d9aea4e49580fa1d4","product_id":"CSAFPID-5","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*"}}},{"category":"product_version_range","name":">=14909664e4e192f4c6f6fcdccd9919af7cf783ab <2fa49b2715e1bad12ce3b0fa64e234d9582c8193","product":{"name":"Linux Linux >=14909664e4e192f4c6f6fcdccd9919af7cf783ab <2fa49b2715e1bad12ce3b0fa64e234d9582c8193","product_id":"CSAFPID-6","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*"}}},{"category":"product_version_range","name":">=14909664e4e192f4c6f6fcdccd9919af7cf783ab <cb658c2f5f7977c2a1c77c9f239f4bc8196edb5c","product":{"name":"Linux Linux >=14909664e4e192f4c6f6fcdccd9919af7cf783ab <cb658c2f5f7977c2a1c77c9f239f4bc8196edb5c","product_id":"CSAFPID-7","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*"}}},{"category":"product_version_range","name":">=14909664e4e192f4c6f6fcdccd9919af7cf783ab <f0e42f0c4337b1f220de1ddd63f47197c7dee4de","product":{"name":"Linux Linux >=14909664e4e192f4c6f6fcdccd9919af7cf783ab <f0e42f0c4337b1f220de1ddd63f47197c7dee4de","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":"3.18","product":{"name":"Linux Linux 3.18","product_id":"CSAFPID-9","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:3.18:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"0","product":{"name":"Linux Linux 0","product_id":"CSAFPID-10","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:3.18:*:*:*:*:*:*:*"}}},{"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:3.18:*:*:*:*:*:*:*"}}},{"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:3.18:*:*:*:*:*:*:*"}}},{"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:3.18:*:*:*:*:*:*:*"}}},{"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:3.18:*:*:*:*:*:*:*"}}},{"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:3.18:*:*:*:*:*:*:*"}}},{"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:3.18:*:*:*:*:*:*:*"}}},{"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:3.18:*:*:*:*:*:*:*"}}},{"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:3.18:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-53228","title":"ipv6: sit: reload inner IPv6 header after GSO offloads","notes":[{"category":"description","text":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: sit: reload inner IPv6 header after GSO offloads\n\nipip6_tunnel_xmit() caches the inner IPv6 header pointer at function\nentry and continues using it after iptunnel_handle_offloads().\n\nFor GSO skbs, iptunnel_handle_offloads() calls skb_header_unclone().\nWhen the skb header is cloned, skb_header_unclone() can call\npskb_expand_head(), which may move the skb head. The pskb_expand_head()\ncontract requires pointers into the skb header to be reloaded after the\ncall.\n\nIf the later skb_realloc_headroom() branch is not taken, SIT uses the\nstale iph6 pointer to read the inner hop limit and DS field. That can\nread from a freed skb head after the old head's remaining clone is\nreleased.\n\nReload iph6 after the offload helper succeeds and before subsequent\nreads from the inner IPv6 header. Keep the existing reload after\nskb_realloc_headroom(), since that branch can also replace the skb.","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, 0bfa7bba1f41aaf5f0604dc712bb4701493e3aa0, 1132e5edc2866c3530be17622153a597095f0e43, 2fa49b2715e1bad12ce3b0fa64e234d9582c8193, 5.10.259, 5.15.210, 59f80c919713250fe5d25a4d9aea4e49580fa1d4, 6.1.176, 6.6.143, 6.12.94, 6.18.36, 7.0.13, 7.1, 9c67b44edb3598d234efae6e44649eb993c03da5, cb658c2f5f7977c2a1c77c9f239f4bc8196edb5c, f0e42f0c4337b1f220de1ddd63f47197c7dee4de, fddd41445a0537b093e6b3f6232c9933cad1e48b.","product_ids":["CSAFPID-1","CSAFPID-2","CSAFPID-3","CSAFPID-4","CSAFPID-5","CSAFPID-6","CSAFPID-7","CSAFPID-8","CSAFPID-9"]}]}]}