{"id":"CVE-2026-80839","revision":"4a48aa85d69e49e4877085fd5e9d11c1","records":[{"revision":"4a48aa85d69e49e4877085fd5e9d11c1","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-80839","aliases":[],"title":"batman-adv: reject unrepresentable multicast TVLV offsets","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: reject unrepresentable multicast TVLV offsets\n\nThe network and transport header fields in struct sk_buff are 16-bit\noffsets from skb->head, and U16_MAX is reserved as the unset transport\nheader value. batadv_tvlv_call_handler() sets both fields from a received\nmulticast TVLV without checking whether the TVLV end is representable.\n\nIf the end offset exceeds the field's range, skb_set_transport_header()\ntruncates it so that the transport header precedes the network header.\nThe negative difference is then returned by skb_network_header_len() as\na large u32. batadv_mcast_forw_packet() consequently accepts an oversized\nmulticast tracker and accesses memory beyond the skb data.\n\nAdd skb_set_transport_header_careful(), an offset-aware counterpart to\nskb_reset_transport_header_careful(), which validates the final\nhead-relative offset before assigning it. Use the new helper in\nbatadv_tvlv_call_handler() and reject unrepresentable TVLVs before\nsetting the network header.","state":0,"publishedAt":"2026-09-04T15:54:49.378+00:00","modifiedAt":"2026-10-19T08:44:32.478+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                        \"include/linux/skbuff.h\",\n                        \"net/batman-adv/tvlv.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"07afe1ba288c04280622fa002ed385f1ac0b6fe6\",\n                            \"lessThan\": \"da1f5aa7ec93f2cc17f5cd30efc54f62af433cf2\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"07afe1ba288c04280622fa002ed385f1ac0b6fe6\",\n                            \"lessThan\": \"916ec741e65af072b98e475feaad98c063da1b7c\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"07afe1ba288c04280622fa002ed385f1ac0b6fe6\",\n                            \"lessThan\": \"1b466746fe109127fd983100a228cdd1f1f6ece2\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"07afe1ba288c04280622fa002ed385f1ac0b6fe6\",\n                            \"lessThan\": \"2b46baa591d0a7c16b62f150917187e70d053be6\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"07afe1ba288c04280622fa002ed385f1ac0b6fe6\",\n                            \"lessThan\": \"f12c2de4f542e3220e17e0606f492110064f04cb\",\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                        \"include/linux/skbuff.h\",\n                        \"net/batman-adv/tvlv.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.8\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.8\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.108\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.49\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.1.13\",\n                            \"lessThanOrEqual\": \"7.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.3\",\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/da1f5aa7ec93f2cc17f5cd30efc54f62af433cf2","https://git.kernel.org/stable/c/916ec741e65af072b98e475feaad98c063da1b7c","https://git.kernel.org/stable/c/1b466746fe109127fd983100a228cdd1f1f6ece2","https://git.kernel.org/stable/c/2b46baa591d0a7c16b62f150917187e70d053be6","https://git.kernel.org/stable/c/f12c2de4f542e3220e17e0606f492110064f04cb"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-80839","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-80839","identifiers":["CVE-2026-80839"]},"retained":false,"historicalAffected":[]}],"coverage":[]}