{"api_version":"1","generated_at":"2026-09-26T09:50:54+00:00","cve":"CVE-2026-98096","urls":{"html":"https://cve.report/CVE-2026-98096","api":"https://cve.report/api/cve/CVE-2026-98096.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-98096","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-98096"},"summary":{"title":"ipv6: sr: restore network header before routing and forwarding","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: sr: restore network header before routing and forwarding\n\nipv6_srh_rcv() runs with skb->data at the Segment Routing Header (SRH)\nwhile skb_network_header() points at the IPv6 header.\n\nWhen segments_left > 0, ipv6_srh_rcv() previously restored the skb->data\nposition by pushing sizeof(struct ipv6hdr), assuming the SRH immediately\nfollowed the fixed IPv6 header. If another extension header (such as a\nHop-by-Hop options header) precedes the SRH, skb_network_offset()\nremained negative.\n\nThis led to two problems:\n1. During ip6_route_input(), fib6_rules_early_flow_dissect() invokes\n   __skb_flow_dissect() which passes the negative skb_network_offset()\n   to flow dissection, breaking BPF and C flow dissector logic.\n2. If forwarded via ip6_forward() or redirected via act_mirred, downstream\n   handlers (like sch_fragment() or neighbour output) pass the negative\n   offset as an unsigned length, triggering OOB memcpy or buffer overflows.\n\nFix this by pushing -skb_network_offset(skb) before routing, ensuring\nskb_network_offset(skb) is 0 for route lookup / flow dissection as well as\ndownstream forwarding. On the loopback path, pull skb_transport_offset(skb)\nto restore skb->data to the SRH before looping back.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-25 11:17:39","updated_at":"2026-09-25 15:18:05"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.4","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H","baseScore":7.4,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.4","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H","data":{"baseScore":7.4,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/3ad7dca5e03bd64c65983a19734337512fd75491","name":"https://git.kernel.org/stable/c/3ad7dca5e03bd64c65983a19734337512fd75491","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/97b21ef57dfabbff660a4672c9fef7edfb720f47","name":"https://git.kernel.org/stable/c/97b21ef57dfabbff660a4672c9fef7edfb720f47","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ce4c8beedc19aceeab0e7bdc6f34394fb158c47c","name":"https://git.kernel.org/stable/c/ce4c8beedc19aceeab0e7bdc6f34394fb158c47c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/975b5b067f525a1b1338c4a3bee1c46545801518","name":"https://git.kernel.org/stable/c/975b5b067f525a1b1338c4a3bee1c46545801518","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-98096","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98096","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1ababeba4a21f3dba3da3523c670b207fb2feb62 ce4c8beedc19aceeab0e7bdc6f34394fb158c47c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1ababeba4a21f3dba3da3523c670b207fb2feb62 97b21ef57dfabbff660a4672c9fef7edfb720f47 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1ababeba4a21f3dba3da3523c670b207fb2feb62 3ad7dca5e03bd64c65983a19734337512fd75491 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1ababeba4a21f3dba3da3523c670b207fb2feb62 975b5b067f525a1b1338c4a3bee1c46545801518 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.10","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 4.10 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.111 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.53 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.7 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/ipv6/exthdrs.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"ce4c8beedc19aceeab0e7bdc6f34394fb158c47c","status":"affected","version":"1ababeba4a21f3dba3da3523c670b207fb2feb62","versionType":"git"},{"lessThan":"97b21ef57dfabbff660a4672c9fef7edfb720f47","status":"affected","version":"1ababeba4a21f3dba3da3523c670b207fb2feb62","versionType":"git"},{"lessThan":"3ad7dca5e03bd64c65983a19734337512fd75491","status":"affected","version":"1ababeba4a21f3dba3da3523c670b207fb2feb62","versionType":"git"},{"lessThan":"975b5b067f525a1b1338c4a3bee1c46545801518","status":"affected","version":"1ababeba4a21f3dba3da3523c670b207fb2feb62","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/ipv6/exthdrs.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"4.10"},{"lessThan":"4.10","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.111","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.53","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.7","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.111","versionStartIncluding":"4.10","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.53","versionStartIncluding":"4.10","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.7","versionStartIncluding":"4.10","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc2","versionStartIncluding":"4.10","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: sr: restore network header before routing and forwarding\n\nipv6_srh_rcv() runs with skb->data at the Segment Routing Header (SRH)\nwhile skb_network_header() points at the IPv6 header.\n\nWhen segments_left > 0, ipv6_srh_rcv() previously restored the skb->data\nposition by pushing sizeof(struct ipv6hdr), assuming the SRH immediately\nfollowed the fixed IPv6 header. If another extension header (such as a\nHop-by-Hop options header) precedes the SRH, skb_network_offset()\nremained negative.\n\nThis led to two problems:\n1. During ip6_route_input(), fib6_rules_early_flow_dissect() invokes\n   __skb_flow_dissect() which passes the negative skb_network_offset()\n   to flow dissection, breaking BPF and C flow dissector logic.\n2. If forwarded via ip6_forward() or redirected via act_mirred, downstream\n   handlers (like sch_fragment() or neighbour output) pass the negative\n   offset as an unsigned length, triggering OOB memcpy or buffer overflows.\n\nFix this by pushing -skb_network_offset(skb) before routing, ensuring\nskb_network_offset(skb) is 0 for route lookup / flow dissection as well as\ndownstream forwarding. On the loopback path, pull skb_transport_offset(skb)\nto restore skb->data to the SRH before looping back."}],"metrics":[{"cvssV3_1":{"baseScore":7.4,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:N - The bad input is a routed IPv6 packet sent by a remote host: a Hop-by-Hop header followed by an SRH with segments_left>0. ipv6_srh_rcv() processes it on receive, and its fixed skb_push(sizeof(struct ipv6hdr)) leaves skb_network_offset() negative before ip6_route_input() and dst_input() forward the packet.\nAC:H - ipv6_srh_rcv() drops the packet unless seg6_enabled, which defaults to 0, is set both in devconf_all and on the ingress interface. The out-of-bounds memcpy in sch_frag_prepare_frag() also needs the admin to have set up tc act_ct with an MRU plus act_mirred on the forwarding path. The remote attacker cannot set up either of these.\nPR:N - No authentication is needed to send the packet. seg6_hmac_validate_skb() accepts SRHs that carry no HMAC TLV when seg6_require_hmac is at its default of 0, so an unauthenticated sender reaches the segments_left>0 branch.\nUI:N - No victim action is needed. The router processes the attacker's SRH packet in softirq receive context as soon as it arrives.\nS:U - The corruption stays inside the router's own kernel (skb metadata, then the per-CPU sch_frag_data_storage and memory after it). No VM, IOMMU or sandbox boundary is crossed.\nC:N - With the negative offset, the flow dissector and the neighbour output path read or write inside the skb head, and the bytes sch_frag reads out of bounds go into per-CPU storage. I found no path that sends kernel memory back to the attacker.\nI:H - sch_frag_prepare_frag() takes the negative skb_network_offset() as unsigned hlen and runs memcpy(&data->l2_data, skb->data, hlen). That writes packet bytes the attacker supplied past the per-CPU sch_frag_data_storage buffer, an out-of-bounds kernel write.\nA:H - The roughly 4 GB memcpy in sch_frag_prepare_frag() will fault and crash the router. On other paths the negative offset breaks flow dissection and garbles forwarded packets. The attacker can repeat this with each crafted packet."}]}],"providerMetadata":{"dateUpdated":"2026-09-25T14:42:04.399Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/ce4c8beedc19aceeab0e7bdc6f34394fb158c47c"},{"url":"https://git.kernel.org/stable/c/97b21ef57dfabbff660a4672c9fef7edfb720f47"},{"url":"https://git.kernel.org/stable/c/3ad7dca5e03bd64c65983a19734337512fd75491"},{"url":"https://git.kernel.org/stable/c/975b5b067f525a1b1338c4a3bee1c46545801518"}],"title":"ipv6: sr: restore network header before routing and forwarding","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-98096","datePublished":"2026-09-25T10:24:27.098Z","dateReserved":"2026-09-25T10:19:56.076Z","dateUpdated":"2026-09-25T14:42:04.399Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-25 11:17:39","lastModifiedDate":"2026-09-25 15:18:05","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H","baseScore":7.4,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":2.2,"impactScore":5.2}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"98096","Ordinal":"1","Title":"ipv6: sr: restore network header before routing and forwarding","CVE":"CVE-2026-98096","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"98096","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: sr: restore network header before routing and forwarding\n\nipv6_srh_rcv() runs with skb->data at the Segment Routing Header (SRH)\nwhile skb_network_header() points at the IPv6 header.\n\nWhen segments_left > 0, ipv6_srh_rcv() previously restored the skb->data\nposition by pushing sizeof(struct ipv6hdr), assuming the SRH immediately\nfollowed the fixed IPv6 header. If another extension header (such as a\nHop-by-Hop options header) precedes the SRH, skb_network_offset()\nremained negative.\n\nThis led to two problems:\n1. During ip6_route_input(), fib6_rules_early_flow_dissect() invokes\n   __skb_flow_dissect() which passes the negative skb_network_offset()\n   to flow dissection, breaking BPF and C flow dissector logic.\n2. If forwarded via ip6_forward() or redirected via act_mirred, downstream\n   handlers (like sch_fragment() or neighbour output) pass the negative\n   offset as an unsigned length, triggering OOB memcpy or buffer overflows.\n\nFix this by pushing -skb_network_offset(skb) before routing, ensuring\nskb_network_offset(skb) is 0 for route lookup / flow dissection as well as\ndownstream forwarding. On the loopback path, pull skb_transport_offset(skb)\nto restore skb->data to the SRH before looping back.","Type":"Description","Title":"ipv6: sr: restore network header before routing and forwarding"}]}}}