{"api_version":"1","generated_at":"2026-05-03T12:43:37+00:00","cve":"CVE-2026-43038","urls":{"html":"https://cve.report/CVE-2026-43038","api":"https://cve.report/api/cve/CVE-2026-43038.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-43038","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-43038"},"summary":{"title":"ipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach()\n\nSashiko AI-review observed:\n\n  In ip6_err_gen_icmpv6_unreach(), the skb is an outer IPv4 ICMP error packet\n  where its cb contains an IPv4 inet_skb_parm. When skb is cloned into skb2\n  and passed to icmp6_send(), it uses IP6CB(skb2).\n\n  IP6CB interprets the IPv4 inet_skb_parm as an inet6_skb_parm. The cipso\n  offset in inet_skb_parm.opt directly overlaps with dsthao in inet6_skb_parm\n  at offset 18.\n\n  If an attacker sends a forged ICMPv4 error with a CIPSO IP option, dsthao\n  would be a non-zero offset. Inside icmp6_send(), mip6_addr_swap() is called\n  and uses ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO).\n\n  This would scan the inner, attacker-controlled IPv6 packet starting at that\n  offset, potentially returning a fake TLV without checking if the remaining\n  packet length can hold the full 18-byte struct ipv6_destopt_hao.\n\n  Could mip6_addr_swap() then perform a 16-byte swap that extends past the end\n  of the packet data into skb_shared_info?\n\n  Should the cb array also be cleared in ip6_err_gen_icmpv6_unreach() and\n  ip6ip6_err() to prevent this?\n\nThis patch implements the first suggestion.\n\nI am not sure if ip6ip6_err() needs to be changed.\nA separate patch would be better anyway.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-05-01 15:16:48","updated_at":"2026-05-03 07:16:23"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"9.8","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"9.8","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":9.8,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/3d5127d998de617b130aae96b138dba22ac6a8a7","name":"https://git.kernel.org/stable/c/3d5127d998de617b130aae96b138dba22ac6a8a7","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a4437faf135da293d16fcc4cc607316742bd0ebb","name":"https://git.kernel.org/stable/c/a4437faf135da293d16fcc4cc607316742bd0ebb","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0452b6526b2f54b2413b9cb4ff1ea2ac542c99c7","name":"https://git.kernel.org/stable/c/0452b6526b2f54b2413b9cb4ff1ea2ac542c99c7","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a2edbb6393972a02114b6003953a5cef3104fada","name":"https://git.kernel.org/stable/c/a2edbb6393972a02114b6003953a5cef3104fada","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/86ab3e55673a7a49a841838776f1ab18d23a67b5","name":"https://git.kernel.org/stable/c/86ab3e55673a7a49a841838776f1ab18d23a67b5","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/c438ba010171b70bad22fc18b1d5bdc3627476e8","name":"https://git.kernel.org/stable/c/c438ba010171b70bad22fc18b1d5bdc3627476e8","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1ceeebd5bd6d855b17a5df625109bfe29129d7cf","name":"https://git.kernel.org/stable/c/1ceeebd5bd6d855b17a5df625109bfe29129d7cf","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e41953e7d118e2702bcb217879c173d9d1d3cd4e","name":"https://git.kernel.org/stable/c/e41953e7d118e2702bcb217879c173d9d1d3cd4e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-43038","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-43038","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ca15a078bd907df5fc1c009477869c5cbde3b753 c438ba010171b70bad22fc18b1d5bdc3627476e8 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ca15a078bd907df5fc1c009477869c5cbde3b753 0452b6526b2f54b2413b9cb4ff1ea2ac542c99c7 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ca15a078bd907df5fc1c009477869c5cbde3b753 a4437faf135da293d16fcc4cc607316742bd0ebb git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ca15a078bd907df5fc1c009477869c5cbde3b753 3d5127d998de617b130aae96b138dba22ac6a8a7 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ca15a078bd907df5fc1c009477869c5cbde3b753 e41953e7d118e2702bcb217879c173d9d1d3cd4e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ca15a078bd907df5fc1c009477869c5cbde3b753 a2edbb6393972a02114b6003953a5cef3104fada git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ca15a078bd907df5fc1c009477869c5cbde3b753 1ceeebd5bd6d855b17a5df625109bfe29129d7cf git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ca15a078bd907df5fc1c009477869c5cbde3b753 86ab3e55673a7a49a841838776f1ab18d23a67b5 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 3.13","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 3.13 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.10.253 5.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.203 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.168 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.134 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.81 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.22 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.19.12 6.19.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"43038","cve":"CVE-2026-43038","epss":"0.000240000","percentile":"0.068220000","score_date":"2026-05-02","updated_at":"2026-05-03 00:00:23"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/ipv6/icmp.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"c438ba010171b70bad22fc18b1d5bdc3627476e8","status":"affected","version":"ca15a078bd907df5fc1c009477869c5cbde3b753","versionType":"git"},{"lessThan":"0452b6526b2f54b2413b9cb4ff1ea2ac542c99c7","status":"affected","version":"ca15a078bd907df5fc1c009477869c5cbde3b753","versionType":"git"},{"lessThan":"a4437faf135da293d16fcc4cc607316742bd0ebb","status":"affected","version":"ca15a078bd907df5fc1c009477869c5cbde3b753","versionType":"git"},{"lessThan":"3d5127d998de617b130aae96b138dba22ac6a8a7","status":"affected","version":"ca15a078bd907df5fc1c009477869c5cbde3b753","versionType":"git"},{"lessThan":"e41953e7d118e2702bcb217879c173d9d1d3cd4e","status":"affected","version":"ca15a078bd907df5fc1c009477869c5cbde3b753","versionType":"git"},{"lessThan":"a2edbb6393972a02114b6003953a5cef3104fada","status":"affected","version":"ca15a078bd907df5fc1c009477869c5cbde3b753","versionType":"git"},{"lessThan":"1ceeebd5bd6d855b17a5df625109bfe29129d7cf","status":"affected","version":"ca15a078bd907df5fc1c009477869c5cbde3b753","versionType":"git"},{"lessThan":"86ab3e55673a7a49a841838776f1ab18d23a67b5","status":"affected","version":"ca15a078bd907df5fc1c009477869c5cbde3b753","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/ipv6/icmp.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"3.13"},{"lessThan":"3.13","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.253","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.203","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.168","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.134","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.81","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.22","versionType":"semver"},{"lessThanOrEqual":"6.19.*","status":"unaffected","version":"6.19.12","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.0","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.253","versionStartIncluding":"3.13","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.203","versionStartIncluding":"3.13","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.168","versionStartIncluding":"3.13","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.134","versionStartIncluding":"3.13","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.81","versionStartIncluding":"3.13","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.22","versionStartIncluding":"3.13","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.19.12","versionStartIncluding":"3.13","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0","versionStartIncluding":"3.13","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach()\n\nSashiko AI-review observed:\n\n  In ip6_err_gen_icmpv6_unreach(), the skb is an outer IPv4 ICMP error packet\n  where its cb contains an IPv4 inet_skb_parm. When skb is cloned into skb2\n  and passed to icmp6_send(), it uses IP6CB(skb2).\n\n  IP6CB interprets the IPv4 inet_skb_parm as an inet6_skb_parm. The cipso\n  offset in inet_skb_parm.opt directly overlaps with dsthao in inet6_skb_parm\n  at offset 18.\n\n  If an attacker sends a forged ICMPv4 error with a CIPSO IP option, dsthao\n  would be a non-zero offset. Inside icmp6_send(), mip6_addr_swap() is called\n  and uses ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO).\n\n  This would scan the inner, attacker-controlled IPv6 packet starting at that\n  offset, potentially returning a fake TLV without checking if the remaining\n  packet length can hold the full 18-byte struct ipv6_destopt_hao.\n\n  Could mip6_addr_swap() then perform a 16-byte swap that extends past the end\n  of the packet data into skb_shared_info?\n\n  Should the cb array also be cleared in ip6_err_gen_icmpv6_unreach() and\n  ip6ip6_err() to prevent this?\n\nThis patch implements the first suggestion.\n\nI am not sure if ip6ip6_err() needs to be changed.\nA separate patch would be better anyway."}],"metrics":[{"cvssV3_1":{"baseScore":9.8,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"providerMetadata":{"dateUpdated":"2026-05-03T05:46:17.465Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/c438ba010171b70bad22fc18b1d5bdc3627476e8"},{"url":"https://git.kernel.org/stable/c/0452b6526b2f54b2413b9cb4ff1ea2ac542c99c7"},{"url":"https://git.kernel.org/stable/c/a4437faf135da293d16fcc4cc607316742bd0ebb"},{"url":"https://git.kernel.org/stable/c/3d5127d998de617b130aae96b138dba22ac6a8a7"},{"url":"https://git.kernel.org/stable/c/e41953e7d118e2702bcb217879c173d9d1d3cd4e"},{"url":"https://git.kernel.org/stable/c/a2edbb6393972a02114b6003953a5cef3104fada"},{"url":"https://git.kernel.org/stable/c/1ceeebd5bd6d855b17a5df625109bfe29129d7cf"},{"url":"https://git.kernel.org/stable/c/86ab3e55673a7a49a841838776f1ab18d23a67b5"}],"title":"ipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-43038","datePublished":"2026-05-01T14:15:35.986Z","dateReserved":"2026-05-01T14:12:55.978Z","dateUpdated":"2026-05-03T05:46:17.465Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-05-01 15:16:48","lastModifiedDate":"2026-05-03 07:16:23","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"43038","Ordinal":"1","Title":"ipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach()","CVE":"CVE-2026-43038","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"43038","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach()\n\nSashiko AI-review observed:\n\n  In ip6_err_gen_icmpv6_unreach(), the skb is an outer IPv4 ICMP error packet\n  where its cb contains an IPv4 inet_skb_parm. When skb is cloned into skb2\n  and passed to icmp6_send(), it uses IP6CB(skb2).\n\n  IP6CB interprets the IPv4 inet_skb_parm as an inet6_skb_parm. The cipso\n  offset in inet_skb_parm.opt directly overlaps with dsthao in inet6_skb_parm\n  at offset 18.\n\n  If an attacker sends a forged ICMPv4 error with a CIPSO IP option, dsthao\n  would be a non-zero offset. Inside icmp6_send(), mip6_addr_swap() is called\n  and uses ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO).\n\n  This would scan the inner, attacker-controlled IPv6 packet starting at that\n  offset, potentially returning a fake TLV without checking if the remaining\n  packet length can hold the full 18-byte struct ipv6_destopt_hao.\n\n  Could mip6_addr_swap() then perform a 16-byte swap that extends past the end\n  of the packet data into skb_shared_info?\n\n  Should the cb array also be cleared in ip6_err_gen_icmpv6_unreach() and\n  ip6ip6_err() to prevent this?\n\nThis patch implements the first suggestion.\n\nI am not sure if ip6ip6_err() needs to be changed.\nA separate patch would be better anyway.","Type":"Description","Title":"ipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach()"}]}}}