{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-43501", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-01T14:12:56.014Z", "datePublished": "2026-05-21T12:17:49.885Z", "dateUpdated": "2026-05-21T12:17:49.885Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-21T12:17:49.885Z"}, "descriptions": [{"lang": "en", "value": "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."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/ipv6/exthdrs.c"], "versions": [{"version": "8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3", "lessThan": "8e8be63465a5e80394c70324603dfea1bfdad48f", "status": "affected", "versionType": "git"}, {"version": "8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3", "lessThan": "4babc2d9fda2df43823b85d08a0180b68f1b0854", "status": "affected", "versionType": "git"}, {"version": "8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3", "lessThan": "c261d07a80576dc8ccf394ef8f074f8c67a06b37", "status": "affected", "versionType": "git"}, {"version": "8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3", "lessThan": "7398ebefbfd4f8a31d4f665a4213302fa995494b", "status": "affected", "versionType": "git"}, {"version": "8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3", "lessThan": "9e6bf146b55999a095bb14f73a843942456d1adc", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/ipv6/exthdrs.c"], "versions": [{"version": "5.7", "status": "affected"}, {"version": "0", "lessThan": "5.7", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.140", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.86", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.27", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.0.4", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1-rc2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.6.140"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.12.86"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.18.27"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "7.0.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "7.1-rc2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/8e8be63465a5e80394c70324603dfea1bfdad48f"}, {"url": "https://git.kernel.org/stable/c/4babc2d9fda2df43823b85d08a0180b68f1b0854"}, {"url": "https://git.kernel.org/stable/c/c261d07a80576dc8ccf394ef8f074f8c67a06b37"}, {"url": "https://git.kernel.org/stable/c/7398ebefbfd4f8a31d4f665a4213302fa995494b"}, {"url": "https://git.kernel.org/stable/c/9e6bf146b55999a095bb14f73a843942456d1adc"}], "title": "ipv6: rpl: reserve mac_len headroom when recompressed SRH grows", "x_generator": {"engine": "bippy-1.2.0"}}}}