{"cve":"CVE-2026-98371","nvd":{"published":"2026-10-06T09:18:31.613","modified":"2026-10-19T10:18:40.323","status":"Received","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.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/5b8afb56ccb7c014b0f1ac40341708b200443c2d","https://git.kernel.org/stable/c/a7018ee0ea8622ed59edc064be4e0f2c26464f53","https://git.kernel.org/stable/c/dc33262be1fe43d0eb0b84fb58c6ed42e2f64a8c"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:57:46.668721662+00:00"},"epss":{"cve":"CVE-2026-98371","score":0.00162,"percentile":0.05291,"date":"2026-10-26"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}