{"cvss":9.8,"datePublished":"2026-05-21T13:16:19.410","dateUpdated":"2026-09-08T09:18:05.747","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: rpl: reserve mac_len headroom when recompressed SRH grows\n\nipv6_rpl_srh_rcv() decompresses an RFC 6554 Source Routing Header, swaps\nthe next segment into ipv6_hdr->daddr, recompresses, then pulls the old\nheader and pushes the new one plus the IPv6 header back.  The\nrecompressed header can be larger than the received one when the swap\nreduces the common-prefix length the segments share with daddr (CmprI=0,\nCmprE>0, seg[0][0] != daddr[0] gives the maximum +8 bytes).\n\npskb_expand_head() was gated on segments_left == 0, so on earlier\nsegments the push consumed unchecked headroom.  Once skb_push() leaves\nfewer than skb->mac_len bytes in front of data,\nskb_mac_header_rebuild()'s call to:\n\n\tskb_set_mac_header(skb, -skb->mac_len);\n\nwill store (data - head) - mac_len into the u16 mac_header field, which\nwraps to ~65530, and the following memmove() writes mac_len bytes ~64KiB\npast skb->head.\n\nA single AF_INET6/SOCK_RAW/IPV6_HDRINCL packet over lo with a two\nsegment type-3 SRH (CmprI=0, CmprE=15) reaches headroom 8 after one\npass; KASAN reports a 14-byte OOB write in ipv6_rthdr_rcv.\n\nFix this by expanding the head whenever the remaining room is less than\nthe push size plus mac_len, and request that much extra so the rebuilt\nMAC header fits afterwards.","id":"CVE-2026-43501","raw":{"affected":[{"affectedData":[{"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":"bde199c72d319a4e207f88daabc888317504e2fb","status":"affected","version":"8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3","versionType":"git"},{"lessThan":"be1fa0aa9b4fdd5a8b7a61ba520a690a68391e6e","status":"affected","version":"8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3","versionType":"git"},{"lessThan":"0a9e8053f1f8a8e1bfc1dd61ffe67be6c1180402","status":"affected","version":"8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3","versionType":"git"},{"lessThan":"8e8be63465a5e80394c70324603dfea1bfdad48f","status":"affected","version":"8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3","versionType":"git"},{"lessThan":"4babc2d9fda2df43823b85d08a0180b68f1b0854","status":"affected","version":"8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3","versionType":"git"},{"lessThan":"c261d07a80576dc8ccf394ef8f074f8c67a06b37","status":"affected","version":"8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3","versionType":"git"},{"lessThan":"7398ebefbfd4f8a31d4f665a4213302fa995494b","status":"affected","version":"8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3","versionType":"git"},{"lessThan":"9e6bf146b55999a095bb14f73a843942456d1adc","status":"affected","version":"8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3","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":"5.7"},{"lessThan":"5.7","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.258","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.209","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.175","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.140","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.86","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.27","versionType":"semver"},{"lessThanOrEqual":"7.0.*","status":"unaffected","version":"7.0.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.1","versionType":"original_commit_for_fix"}]}],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"affectedData":[{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:10.2"],"defaultStatus":"affected","packageName":"kernel","product":"Red 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Hat"},{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:8"],"defaultStatus":"unaffected","packageName":"kernel","product":"Red Hat Enterprise Linux 8","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:8"],"defaultStatus":"unaffected","packageName":"kernel-rt","product":"Red Hat Enterprise Linux 8","vendor":"Red Hat"},{"collectionURL":"https://access.redhat.com/downloads/content/package-browser/","cpes":["cpe:/o:redhat:enterprise_linux:9"],"defaultStatus":"affected","packageName":"kernel-rt","product":"Red Hat Enterprise Linux 9","vendor":"Red Hat"}],"source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"affectedData":[{"defaultStatus":"unknown","product":"SIMATIC S7-1500 CPU 1518-4 PN/DP 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the Linux kernel, the following vulnerability has been resolved:\n\nipv6: rpl: reserve mac_len headroom when recompressed SRH grows\n\nipv6_rpl_srh_rcv() decompresses an RFC 6554 Source Routing Header, swaps\nthe next segment into ipv6_hdr->daddr, recompresses, then pulls the old\nheader and pushes the new one plus the IPv6 header back.  The\nrecompressed header can be larger than the received one when the swap\nreduces the common-prefix length the segments share with daddr (CmprI=0,\nCmprE>0, seg[0][0] != daddr[0] gives the maximum +8 bytes).\n\npskb_expand_head() was gated on segments_left == 0, so on earlier\nsegments the push consumed unchecked headroom.  Once skb_push() leaves\nfewer than skb->mac_len bytes in front of data,\nskb_mac_header_rebuild()'s call to:\n\n\tskb_set_mac_header(skb, -skb->mac_len);\n\nwill store (data - head) - mac_len into the u16 mac_header field, which\nwraps to ~65530, and the following memmove() writes mac_len bytes ~64KiB\npast skb->head.\n\nA single AF_INET6/SOCK_RAW/IPV6_HDRINCL packet over lo with a two\nsegment type-3 SRH (CmprI=0, CmprE=15) reaches headroom 8 after one\npass; KASAN reports a 14-byte OOB write in ipv6_rthdr_rcv.\n\nFix this by expanding the head whenever the remaining room is less than\nthe push size plus mac_len, and request that much extra so the rebuilt\nMAC header fits afterwards."},{"lang":"es","value":"En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nipv6: rpl: reservar espacio libre (headroom) para mac_len cuando el SRH recomprimido crece\n\nipv6_rpl_srh_rcv() descomprime un encabezado de enrutamiento de origen (Source Routing Header) RFC 6554, intercambia el siguiente segmento en ipv6_hdr->daddr, recomprime, luego extrae el encabezado antiguo y empuja el nuevo más el encabezado IPv6 de vuelta. El encabezado recomprimido puede ser más grande que el recibido cuando el intercambio reduce la longitud del prefijo común que los segmentos comparten con daddr (CmprI=0, CmprE>0, seg[0][0] != daddr[0] da un máximo de +8 bytes).\n\npskb_expand_head() estaba condicionado a segments_left == 0, así que en segmentos anteriores el empuje consumió espacio libre (headroom) sin verificar. Una vez que skb_push() deja menos de skb->mac_len bytes delante de los datos, la llamada de skb_mac_header_rebuild() a:\n\n\tskb_set_mac_header(skb, -skb->mac_len);\n\nalmacenará (data - head) - mac_len en el campo u16 mac_header, que se ajusta a ~65530, y el siguiente memmove() escribe mac_len bytes ~64KiB más allá de skb->head.\n\nUn único paquete AF_INET6/SOCK_RAW/IPV6_HDRINCL sobre lo con un SRH tipo 3 de dos segmentos (CmprI=0, CmprE=15) alcanza un espacio libre (headroom) de 8 después de una pasada; KASAN informa de una escritura OOB de 14 bytes en ipv6_rthdr_rcv.\n\nSolucione esto expandiendo el encabezado siempre que el espacio restante sea menor que el tamaño del empuje más mac_len, y solicite esa cantidad extra para que el encabezado MAC reconstruido quepa después."}],"id":"CVE-2026-43501","lastModified":"2026-09-08T09:18:05.747","metrics":{"cvssMetricV31":[{"cvssData":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":9.8,"baseSeverity":"CRITICAL","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"exploitabilityScore":3.9,"impactScore":5.9,"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary"},{"cvssData":{"attackComplexity":"HIGH","attackVector":"ADJACENT_NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"exploitabilityScore":1.6,"impactScore":5.9,"source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c","type":"Secondary"}]},"published":"2026-05-21T13:16:19.410","references":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"url":"https://git.kernel.org/stable/c/0a9e8053f1f8a8e1bfc1dd61ffe67be6c1180402"},{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"url":"https://git.kernel.org/stable/c/4babc2d9fda2df43823b85d08a0180b68f1b0854"},{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"url":"https://git.kernel.org/stable/c/7398ebefbfd4f8a31d4f665a4213302fa995494b"},{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"url":"https://git.kernel.org/stable/c/8e8be63465a5e80394c70324603dfea1bfdad48f"},{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"url":"https://git.kernel.org/stable/c/9e6bf146b55999a095bb14f73a843942456d1adc"},{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"url":"https://git.kernel.org/stable/c/bde199c72d319a4e207f88daabc888317504e2fb"},{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"url":"https://git.kernel.org/stable/c/be1fa0aa9b4fdd5a8b7a61ba520a690a68391e6e"},{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"url":"https://git.kernel.org/stable/c/c261d07a80576dc8ccf394ef8f074f8c67a06b37"},{"source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c","url":"https://access.redhat.com/errata/RHSA-2026:25191"},{"source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c","url":"https://access.redhat.com/errata/RHSA-2026:25217"},{"source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c","url":"https://access.redhat.com/errata/RHSA-2026:27713"},{"source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c","url":"https://access.redhat.com/errata/RHSA-2026:27731"},{"source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c","url":"https://access.redhat.com/errata/RHSA-2026:33900"},{"source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c","url":"https://access.redhat.com/errata/RHSA-2026:34094"},{"source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c","url":"https://access.redhat.com/errata/RHSA-2026:34095"},{"source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c","url":"https://access.redhat.com/security/cve/CVE-2026-43501"},{"source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2480457"},{"source":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e","url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html"},{"source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-43501.json"}],"sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","vulnStatus":"Modified","weaknesses":[{"description":[{"lang":"en","value":"CWE-787"}],"source":"nvd@nist.gov","type":"Primary"},{"description":[{"lang":"en","value":"CWE-131"}],"source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c","type":"Secondary"}]},"severity":"CRITICAL","source":"nvd","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: rpl: reserve mac_len headroom when recompr..."}