{"id":"CVE-2026-43501","title":"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…","summary":"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…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-787","CWE-131"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 5.7, < 5.10.258","linux_kernel >= 5.11, < 5.15.209","linux_kernel >= 5.16, < 6.1.175","linux_kernel >= 6.2, < 6.6.140","linux_kernel >= 6.7, < 6.12.86","linux_kernel >= 6.13, < 6.18.27","linux_kernel >= 6.19, < 7.0.4","linux_kernel = 7.1"],"patched":["linux_kernel 7.0.4"],"published":"2026-05-21","updated":"2026-09-08","sourceUpdated":"2026-09-08T09:18:05.747","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-43501","references":[{"url":"https://git.kernel.org/stable/c/0a9e8053f1f8a8e1bfc1dd61ffe67be6c1180402","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/4babc2d9fda2df43823b85d08a0180b68f1b0854","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7398ebefbfd4f8a31d4f665a4213302fa995494b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8e8be63465a5e80394c70324603dfea1bfdad48f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9e6bf146b55999a095bb14f73a843942456d1adc","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/bde199c72d319a4e207f88daabc888317504e2fb","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/be1fa0aa9b4fdd5a8b7a61ba520a690a68391e6e","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c261d07a80576dc8ccf394ef8f074f8c67a06b37","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://access.redhat.com/errata/RHSA-2026:25191","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:25217","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:27713","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:27731","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:33900","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:34094","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:34095","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/security/cve/CVE-2026-43501","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2480457","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-43501.json","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}],"tags":["nvd","cve.org","exploit-available"],"epss":0.0065,"epssPercentile":0.49392,"exploits":{"github":2,"githubRepos":["https://github.com/Anyone202/cybermeowfia-termux","https://github.com/ngtuonghung/CVE-2026-43501"],"checkedAt":"2026-09-21T15:28:56.405Z"},"exploitAvailable":true,"ingestedAt":"2026-07-01T16:42:14.750Z","slug":"CVE-2026-43501","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `linux_kernel >= 5.7, < 5.10.258`\n- `linux_kernel >= 5.11, < 5.15.209`\n- `linux_kernel >= 5.16, < 6.1.175`\n- `linux_kernel >= 6.2, < 6.6.140`\n- `linux_kernel >= 6.7, < 6.12.86`\n- `linux_kernel >= 6.13, < 6.18.27`\n- `linux_kernel >= 6.19, < 7.0.4`\n- `linux_kernel = 7.1`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 7.0.4`","depth":"abyssal","depthScore":66,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":5217,"id":"CVE-2026-43501","ts":1788887254022,"field":"exploit_available","old":"false","new":"true"},{"seq":4100,"id":"CVE-2026-43501","ts":1788886369874,"field":"exploit_available","old":"true","new":"false"},{"seq":2876,"id":"CVE-2026-43501","ts":1788883036210,"field":"exploit_available","old":"false","new":"true"},{"seq":1905,"id":"CVE-2026-43501","ts":1788882439291,"field":"exploit_available","old":"true","new":"false"},{"seq":240,"id":"CVE-2026-43501","ts":1788881642651,"field":"exploit_available","old":"false","new":"true"}]}