{"id":"CVE-2026-98371","revision":"a6c4451d8aa44d829ccccd0dd63e4a0f","records":[{"revision":"a6c4451d8aa44d829ccccd0dd63e4a0f","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-98371","aliases":[],"title":"xfrm: iptfs: fix runt reassembly panic from short inner tot_len","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: iptfs: fix runt reassembly panic from short inner tot_len\n\nWhen the start of an inner packet is split across two outer packets\nsuch that fewer than 4 bytes land at the end of the first one,\n__input_process_payload() saves those bytes as a runt and skips the\niplen/iphlen validation performed for in-place packets. When the\ncontinuation packet arrives, iptfs_reassem_cont() only requires the\ndeclared inner length to be >= sizeof(ra_runt) (6) before allocating\nthe reassembly skb with that attacker-controlled length.\n\nHowever, __iptfs_iphlen() always returns the fixed minimum IP header\nsize (20 for IPv4, 40 for IPv6), so for an inner IPv4 tot_len in\n[6, 19] the header-completion copy writes past the declared packet\nlength, and the subsequent \"ipremain -= copylen\" underflows to ~4GB,\nleaving the payload copy length bounded only by blkoff (up to 64KB).\nAt runtime the skb_put() tailroom check turns this into\nskb_over_panic(), i.e. an unprivileged kernel panic (DoS), reachable\nlocally via userns+netns IPTFS SAs and remotely against IPTFS VPN\ngateways when the decrypted outer skb is linear (e.g. AF_PACKET taps,\ntun/tap delivery).\n\nAlign the runt path with the normal path by requiring the declared\ninner length to cover at least the IP header size. This also subsumes\nthe previous >= sizeof(ra_runt) check, since the minimum IP header\nis always larger than the runt buffer.\n\nThis issue was found by the autokbug dynamic kernel fuzzer at\nTencent Yunding Lab.","state":0,"publishedAt":"2026-10-06T08:46:55.753+00:00","modifiedAt":"2026-10-19T09:18:23.197+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/xfrm/xfrm_iptfs.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"07569476544681816335099929ff3494dfbf6b05\",\n                            \"lessThan\": \"a7018ee0ea8622ed59edc064be4e0f2c26464f53\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"07569476544681816335099929ff3494dfbf6b05\",\n                            \"lessThan\": \"5b8afb56ccb7c014b0f1ac40341708b200443c2d\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"07569476544681816335099929ff3494dfbf6b05\",\n                            \"lessThan\": \"dc33262be1fe43d0eb0b84fb58c6ed42e2f64a8c\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/xfrm/xfrm_iptfs.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.14\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.14\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.54\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.8\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/a7018ee0ea8622ed59edc064be4e0f2c26464f53","https://git.kernel.org/stable/c/5b8afb56ccb7c014b0f1ac40341708b200443c2d","https://git.kernel.org/stable/c/dc33262be1fe43d0eb0b84fb58c6ed42e2f64a8c"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98371","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-98371","identifiers":["CVE-2026-98371"]},"retained":false,"historicalAffected":[]}],"coverage":[]}