{"id":"CVE-2026-98802","revision":"bb1973ad90b34f91992f3325fb79a74c","records":[{"revision":"bb1973ad90b34f91992f3325fb79a74c","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-98802","aliases":[],"title":"seg6: ensure packet data is writable before modifying SRH and IPv6 DA","description":"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.","state":0,"publishedAt":"2026-10-18T15:48:49.192+00:00","modifiedAt":"2026-10-19T09:25:55.677+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/ipv6/seg6_local.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"140f04c33bbcf89440dcaf8bef04918abff5a52d\",\n                            \"lessThan\": \"e9141fdb7a2ead48cfcd60c681aba91d3014255b\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"140f04c33bbcf89440dcaf8bef04918abff5a52d\",\n                            \"lessThan\": \"8ae3f4067ba4ae3a15581392f6dac422e3d3def0\",\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/ipv6/seg6_local.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"4.14\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"4.14\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.10\",\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/e9141fdb7a2ead48cfcd60c681aba91d3014255b","https://git.kernel.org/stable/c/8ae3f4067ba4ae3a15581392f6dac422e3d3def0"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98802","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-98802","identifiers":["CVE-2026-98802"]},"retained":false,"historicalAffected":[]}],"coverage":[]}