{"schema":"threatline.record/2","record":{"id":"CVE-2026-99055","aliases":[],"summary":"tcp: reject net_iov in zerocopy receive mapping hints","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: reject net_iov in zerocopy receive mapping hints\n\nAfter copying a readable prefix, receive_fallback_to_copy() asks\ntcp_zerocopy_set_hint_for_skb() where page mapping can resume. If the\nnext skb is unreadable, find_next_mappable_frag() passes its net_iov\nfragment to can_map_frag().\n\nskb_frag_page() returns NULL for a net_iov, but can_map_frag()\ndereferences it in PageCompound(). A v7.2 KASAN run on a connected TCP\nsocket with 64 readable bytes followed by a 4096-byte NET_IOV_DMABUF\nfragment reported:\n\n  BUG: KASAN: null-ptr-deref in can_map_frag\n  tcp_zerocopy_receive -> can_map_frag\n  Kernel panic - not syncing: KASAN: panic_on_warn set\n\nThe diagnostic inserted the net_iov directly because the test host has\nno devmem-capable NIC. Hardware end-to-end reachability remains untested\nand requires CONFIG_NET_DEVMEM plus a supported DMA-buf-bound RX queue.\n\nReject all net_iov fragments before skb_frag_page(). This covers both\nDMABUF and IOURING net_iov types while leaving page-backed checks\nunchanged. With the guard, the same queue copied the readable prefix,\nreturned a 4096-byte skip hint, and completed without a fault.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-99055","source_modified_at":"2026-10-23T12:22:39.451Z","fetched_at":"2026-10-23T18:42:43.628194Z","product":"Linux","vendor":"Linux","versions":[{"version":"9f6b619edf2e85746f261b42ae8f818a59d126f7","lessThan":"563d3564513496b9ce3b3ba7a5154427554d0f06","status":"affected","versionType":"git"},{"version":"9f6b619edf2e85746f261b42ae8f818a59d126f7","lessThan":"1c7463ac0e99cc91c4eecc1b69a740ef1a619932","status":"affected","versionType":"git"},{"version":"9f6b619edf2e85746f261b42ae8f818a59d126f7","lessThan":"3aa6f536a95eb0617c313ae2eb76fdfa85331f85","status":"affected","versionType":"git"},{"version":"9f6b619edf2e85746f261b42ae8f818a59d126f7","lessThan":"8b1f0af1fd5fd113432233ed8a3862ee7c30a84f","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-99055","source_modified_at":"2026-10-23T12:22:39.451Z","fetched_at":"2026-10-23T18:42:43.628194Z","product":"Linux","vendor":"Linux","versions":[{"version":"6.12","status":"affected"},{"version":"0","lessThan":"6.12","status":"unaffected","versionType":"semver"},{"version":"6.12.113","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.57","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.11","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-99055","source_modified_at":"2026-10-23T12:22:39.451Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"563d3564513496b9ce3b3ba7a5154427554d0f06","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-99055","source_modified_at":"2026-10-23T12:22:39.451Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"1c7463ac0e99cc91c4eecc1b69a740ef1a619932","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-99055","source_modified_at":"2026-10-23T12:22:39.451Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"3aa6f536a95eb0617c313ae2eb76fdfa85331f85","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-99055","source_modified_at":"2026-10-23T12:22:39.451Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"8b1f0af1fd5fd113432233ed8a3862ee7c30a84f","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":null,"percentile":null,"score_date":null},"published_at":"2026-10-23T12:22:39.451Z","modified_at":"2026-10-23T12:22:39.451Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-99055","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23T12:22:39.451Z"}],"sources":["CVE List"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/563d3564513496b9ce3b3ba7a5154427554d0f06"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/1c7463ac0e99cc91c4eecc1b69a740ef1a619932"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/3aa6f536a95eb0617c313ae2eb76fdfa85331f85"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/8b1f0af1fd5fd113432233ed8a3862ee7c30a84f"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-23T12:22:39.451Z","content_hash":"98602c8d0150dccfdc268d056c8a77e480691a86f0fbbfdd6149dabd70071a87"}}