{"api_version":"1","generated_at":"2026-09-11T06:37:41+00:00","cve":"CVE-2026-80839","urls":{"html":"https://cve.report/CVE-2026-80839","api":"https://cve.report/api/cve/CVE-2026-80839.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-80839","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-80839"},"summary":{"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":"PUBLISHED","assigner":"Linux","published_at":"2026-09-04 16:18:12","updated_at":"2026-09-04 16:18:12"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/f12c2de4f542e3220e17e0606f492110064f04cb","name":"https://git.kernel.org/stable/c/f12c2de4f542e3220e17e0606f492110064f04cb","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2b46baa591d0a7c16b62f150917187e70d053be6","name":"https://git.kernel.org/stable/c/2b46baa591d0a7c16b62f150917187e70d053be6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1b466746fe109127fd983100a228cdd1f1f6ece2","name":"https://git.kernel.org/stable/c/1b466746fe109127fd983100a228cdd1f1f6ece2","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/916ec741e65af072b98e475feaad98c063da1b7c","name":"https://git.kernel.org/stable/c/916ec741e65af072b98e475feaad98c063da1b7c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/da1f5aa7ec93f2cc17f5cd30efc54f62af433cf2","name":"https://git.kernel.org/stable/c/da1f5aa7ec93f2cc17f5cd30efc54f62af433cf2","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-80839","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80839","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 07afe1ba288c04280622fa002ed385f1ac0b6fe6 da1f5aa7ec93f2cc17f5cd30efc54f62af433cf2 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 07afe1ba288c04280622fa002ed385f1ac0b6fe6 916ec741e65af072b98e475feaad98c063da1b7c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 07afe1ba288c04280622fa002ed385f1ac0b6fe6 1b466746fe109127fd983100a228cdd1f1f6ece2 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 07afe1ba288c04280622fa002ed385f1ac0b6fe6 2b46baa591d0a7c16b62f150917187e70d053be6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 07afe1ba288c04280622fa002ed385f1ac0b6fe6 f12c2de4f542e3220e17e0606f492110064f04cb git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.8","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.8 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.108 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.49 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.13 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.3 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"80839","cve":"CVE-2026-80839","epss":"0.001680000","percentile":"0.063400000","score_date":"2026-09-07","updated_at":"2026-09-08 00:05:27"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["include/linux/skbuff.h","net/batman-adv/tvlv.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"da1f5aa7ec93f2cc17f5cd30efc54f62af433cf2","status":"affected","version":"07afe1ba288c04280622fa002ed385f1ac0b6fe6","versionType":"git"},{"lessThan":"916ec741e65af072b98e475feaad98c063da1b7c","status":"affected","version":"07afe1ba288c04280622fa002ed385f1ac0b6fe6","versionType":"git"},{"lessThan":"1b466746fe109127fd983100a228cdd1f1f6ece2","status":"affected","version":"07afe1ba288c04280622fa002ed385f1ac0b6fe6","versionType":"git"},{"lessThan":"2b46baa591d0a7c16b62f150917187e70d053be6","status":"affected","version":"07afe1ba288c04280622fa002ed385f1ac0b6fe6","versionType":"git"},{"lessThan":"f12c2de4f542e3220e17e0606f492110064f04cb","status":"affected","version":"07afe1ba288c04280622fa002ed385f1ac0b6fe6","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["include/linux/skbuff.h","net/batman-adv/tvlv.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.8"},{"lessThan":"6.8","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.108","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.49","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.13","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.3","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.108","versionStartIncluding":"6.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.49","versionStartIncluding":"6.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.13","versionStartIncluding":"6.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.3","versionStartIncluding":"6.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc1","versionStartIncluding":"6.8","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"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."}],"providerMetadata":{"dateUpdated":"2026-09-04T15:54:49.378Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/da1f5aa7ec93f2cc17f5cd30efc54f62af433cf2"},{"url":"https://git.kernel.org/stable/c/916ec741e65af072b98e475feaad98c063da1b7c"},{"url":"https://git.kernel.org/stable/c/1b466746fe109127fd983100a228cdd1f1f6ece2"},{"url":"https://git.kernel.org/stable/c/2b46baa591d0a7c16b62f150917187e70d053be6"},{"url":"https://git.kernel.org/stable/c/f12c2de4f542e3220e17e0606f492110064f04cb"}],"title":"batman-adv: reject unrepresentable multicast TVLV offsets","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-80839","datePublished":"2026-09-04T15:54:49.378Z","dateReserved":"2026-08-26T14:34:25.796Z","dateUpdated":"2026-09-04T15:54:49.378Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-04 16:18:12","lastModifiedDate":"2026-09-04 16:18:12","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"80839","Ordinal":"1","Title":"batman-adv: reject unrepresentable multicast TVLV offsets","CVE":"CVE-2026-80839","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"80839","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"batman-adv: reject unrepresentable multicast TVLV offsets"}]}}}