{"schema":"threatline.record/2","record":{"id":"CVE-2026-98802","aliases":[],"summary":"seg6: ensure packet data is writable before modifying SRH and IPv6 DA","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nseg6: ensure packet data is writable before modifying SRH and IPv6 DA\n\nadvance_nextseg() modifies the SRH Segments Left field and the IPv6\ndestination address without ensuring the packet data is writable.\nseg6_next_csid_advance_arg() has the same problem when it advances the\nNEXT-C-SID argument in the destination address.\n\nThe skb may be cloned, for example by an AF_PACKET socket receiving on\nthe ingress device. advance_nextseg() and seg6_next_csid_advance_arg()\nthen write into the packet data shared with the clone. A read from that\nsocket can return the modified packet instead of the received one. The\nsimplified path below shows this for advance_nextseg():\n\n__netif_receive_skb_one_core\n  __netif_receive_skb_core\n    deliver_skb               [orig: users=2, cloned=0]\n      packet_rcv\n        skb_clone             clone queued to the AF_PACKET socket\n        consume_skb(orig)     [orig: users=1, cloned=1]\n  ipv6_rcv\n    ip6_rcv_core              skb_share_check: no-op [orig: users=1]\n    [...]\n      input_action_end_core\n        advance_nextseg       writes into the data shared with the clone\n\nCall skb_ensure_writable() in advance_nextseg() and in\nseg6_next_csid_advance_arg() before they modify the packet data.\nskb_ensure_writable() may reallocate skb->head, which invalidates the\npointers into the packet data taken before the call.\nadvance_nextseg() now returns a valid SRH pointer, or NULL if\nskb_ensure_writable() fails.\nseg6_next_csid_advance_arg() takes the pointer to the destination\naddress from the skb after skb_ensure_writable().\nOn failure, the callers drop the packet with SKB_DROP_REASON_NOMEM.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98802","source_modified_at":"2026-10-19T09:25:55.677Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"140f04c33bbcf89440dcaf8bef04918abff5a52d","lessThan":"e9141fdb7a2ead48cfcd60c681aba91d3014255b","status":"affected","versionType":"git"},{"version":"140f04c33bbcf89440dcaf8bef04918abff5a52d","lessThan":"8ae3f4067ba4ae3a15581392f6dac422e3d3def0","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98802","source_modified_at":"2026-10-19T09:25:55.677Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"4.14","status":"affected"},{"version":"0","lessThan":"4.14","status":"unaffected","versionType":"semver"},{"version":"7.2.10","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-2026-98802","source_modified_at":"2026-10-19T09:25:55.677Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"8ae3f4067ba4ae3a15581392f6dac422e3d3def0","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":0.00155,"percentile":0.04319,"score_date":"2026-10-23"},"published_at":"2026-10-18T15:48:49.192Z","modified_at":"2026-10-19T09:25:55.677Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-98802","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-19T09:25:55.677Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98802","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/e9141fdb7a2ead48cfcd60c681aba91d3014255b"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/8ae3f4067ba4ae3a15581392f6dac422e3d3def0"}],"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":"2026-10-19T09:25:55.677Z","content_hash":"47b605918c9298b57a6c4b7d472e1fa9de4c851def396ebd3778ce6970bfeeca"}}