{"api_version":"1","generated_at":"2026-10-21T20:29:13+00:00","cve":"CVE-2026-98371","urls":{"html":"https://cve.report/CVE-2026-98371","api":"https://cve.report/api/cve/CVE-2026-98371.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-98371","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-98371"},"summary":{"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":"PUBLISHED","assigner":"Linux","published_at":"2026-10-06 09:18:31","updated_at":"2026-10-19 10:18:40"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/a7018ee0ea8622ed59edc064be4e0f2c26464f53","name":"https://git.kernel.org/stable/c/a7018ee0ea8622ed59edc064be4e0f2c26464f53","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/dc33262be1fe43d0eb0b84fb58c6ed42e2f64a8c","name":"https://git.kernel.org/stable/c/dc33262be1fe43d0eb0b84fb58c6ed42e2f64a8c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/5b8afb56ccb7c014b0f1ac40341708b200443c2d","name":"https://git.kernel.org/stable/c/5b8afb56ccb7c014b0f1ac40341708b200443c2d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-98371","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98371","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 07569476544681816335099929ff3494dfbf6b05 a7018ee0ea8622ed59edc064be4e0f2c26464f53 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 07569476544681816335099929ff3494dfbf6b05 5b8afb56ccb7c014b0f1ac40341708b200443c2d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 07569476544681816335099929ff3494dfbf6b05 dc33262be1fe43d0eb0b84fb58c6ed42e2f64a8c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.14","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.14 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.54 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.8 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"98371","cve":"CVE-2026-98371","epss":"0.001610000","percentile":"0.047060000","score_date":"2026-10-06","updated_at":"2026-10-07 00:14:55"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/xfrm/xfrm_iptfs.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"a7018ee0ea8622ed59edc064be4e0f2c26464f53","status":"affected","version":"07569476544681816335099929ff3494dfbf6b05","versionType":"git"},{"lessThan":"5b8afb56ccb7c014b0f1ac40341708b200443c2d","status":"affected","version":"07569476544681816335099929ff3494dfbf6b05","versionType":"git"},{"lessThan":"dc33262be1fe43d0eb0b84fb58c6ed42e2f64a8c","status":"affected","version":"07569476544681816335099929ff3494dfbf6b05","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/xfrm/xfrm_iptfs.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.14"},{"lessThan":"6.14","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.54","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.8","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.54","versionStartIncluding":"6.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.8","versionStartIncluding":"6.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3","versionStartIncluding":"6.14","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"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."}],"providerMetadata":{"dateUpdated":"2026-10-19T09:18:23.197Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/a7018ee0ea8622ed59edc064be4e0f2c26464f53"},{"url":"https://git.kernel.org/stable/c/5b8afb56ccb7c014b0f1ac40341708b200443c2d"},{"url":"https://git.kernel.org/stable/c/dc33262be1fe43d0eb0b84fb58c6ed42e2f64a8c"}],"title":"xfrm: iptfs: fix runt reassembly panic from short inner tot_len","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-98371","datePublished":"2026-10-06T08:46:55.753Z","dateReserved":"2026-09-25T10:25:14.344Z","dateUpdated":"2026-10-19T09:18:23.197Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-06 09:18:31","lastModifiedDate":"2026-10-19 10:18:40","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"98371","Ordinal":"1","Title":"xfrm: iptfs: fix runt reassembly panic from short inner tot_len","CVE":"CVE-2026-98371","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"98371","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"xfrm: iptfs: fix runt reassembly panic from short inner tot_len"}]}}}