{"schema_version":"1.7.5","id":"CVE-2026-43037","published":"2026-05-01T14:15:35.314Z","modified":"2026-07-23T18:29:41.323735608Z","related":["ALSA-2026:25120","ALSA-2026:25121","ALSA-2026:25191","ALSA-2026:25217","SUSE-SU-2026:21834-1","SUSE-SU-2026:21841-1","SUSE-SU-2026:21845-1","SUSE-SU-2026:21860-1","SUSE-SU-2026:21876-1","SUSE-SU-2026:21877-1","SUSE-SU-2026:21916-1","SUSE-SU-2026:21919-1","SUSE-SU-2026:2217-1","SUSE-SU-2026:2238-1","SUSE-SU-2026:22598-1","SUSE-SU-2026:22673-1","SUSE-SU-2026:22674-1","SUSE-SU-2026:22675-1","SUSE-SU-2026:22676-1","SUSE-SU-2026:22677-1","SUSE-SU-2026:22678-1","SUSE-SU-2026:22680-1","SUSE-SU-2026:22681-1","SUSE-SU-2026:22682-1","SUSE-SU-2026:22683-1","SUSE-SU-2026:22684-1","SUSE-SU-2026:22685-1","SUSE-SU-2026:22686-1","SUSE-SU-2026:22687-1","SUSE-SU-2026:22689-1","SUSE-SU-2026:22690-1","SUSE-SU-2026:22691-1","SUSE-SU-2026:22692-1","SUSE-SU-2026:22693-1","SUSE-SU-2026:22694-1","SUSE-SU-2026:22695-1","SUSE-SU-2026:22696-1","SUSE-SU-2026:22697-1","SUSE-SU-2026:22711-1","SUSE-SU-2026:22712-1","SUSE-SU-2026:22713-1","SUSE-SU-2026:22714-1","SUSE-SU-2026:22715-1","SUSE-SU-2026:22716-1","SUSE-SU-2026:22717-1","SUSE-SU-2026:22718-1","SUSE-SU-2026:22719-1","SUSE-SU-2026:22720-1","SUSE-SU-2026:22721-1","SUSE-SU-2026:22722-1","SUSE-SU-2026:22723-1","SUSE-SU-2026:22725-1","SUSE-SU-2026:22726-1","SUSE-SU-2026:22728-1","SUSE-SU-2026:22729-1","SUSE-SU-2026:22730-1","SUSE-SU-2026:22731-1","SUSE-SU-2026:22732-1","SUSE-SU-2026:22733-1","SUSE-SU-2026:22734-1","SUSE-SU-2026:22735-1","SUSE-SU-2026:22743-1","SUSE-SU-2026:22744-1","SUSE-SU-2026:22746-1","SUSE-SU-2026:22747-1","SUSE-SU-2026:22748-1","SUSE-SU-2026:22749-1","SUSE-SU-2026:22755-1","SUSE-SU-2026:22758-1","SUSE-SU-2026:22759-1","SUSE-SU-2026:22761-1","SUSE-SU-2026:22762-1","SUSE-SU-2026:22763-1","SUSE-SU-2026:22775-1","SUSE-SU-2026:22776-1","SUSE-SU-2026:22777-1","SUSE-SU-2026:22778-1","SUSE-SU-2026:22780-1","SUSE-SU-2026:22781-1","SUSE-SU-2026:22782-1","SUSE-SU-2026:22783-1","SUSE-SU-2026:22784-1","SUSE-SU-2026:22785-1","SUSE-SU-2026:22786-1","SUSE-SU-2026:2310-1","SUSE-SU-2026:2317-1","SUSE-SU-2026:2331-1","SUSE-SU-2026:2332-1","SUSE-SU-2026:2383-1","SUSE-SU-2026:2421-1","SUSE-SU-2026:2450-1","SUSE-SU-2026:2855-1","SUSE-SU-2026:2857-1","SUSE-SU-2026:2858-1","SUSE-SU-2026:2864-1","SUSE-SU-2026:2866-1","SUSE-SU-2026:2867-1","SUSE-SU-2026:2868-1","SUSE-SU-2026:2887-1","SUSE-SU-2026:2888-1","SUSE-SU-2026:2889-1","SUSE-SU-2026:2890-1","SUSE-SU-2026:2894-1","SUSE-SU-2026:2895-1","SUSE-SU-2026:2899-1","SUSE-SU-2026:2902-1","SUSE-SU-2026:2909-1","SUSE-SU-2026:2910-1","SUSE-SU-2026:2920-1","SUSE-SU-2026:2930-1","SUSE-SU-2026:2932-1","SUSE-SU-2026:2933-1","SUSE-SU-2026:2937-1","SUSE-SU-2026:2938-1","SUSE-SU-2026:2943-1","SUSE-SU-2026:2945-1","SUSE-SU-2026:2955-1","SUSE-SU-2026:2956-1","SUSE-SU-2026:2957-1","SUSE-SU-2026:2961-1","SUSE-SU-2026:2989-1","SUSE-SU-2026:2991-1","SUSE-SU-2026:2992-1","SUSE-SU-2026:2994-1","SUSE-SU-2026:2995-1","SUSE-SU-2026:2997-1","SUSE-SU-2026:3011-1","SUSE-SU-2026:3065-1","SUSE-SU-2026:3066-1","SUSE-SU-2026:3067-1","openSUSE-SU-2026:20826-1"],"summary":"ip6_tunnel: clear skb2->cb[] in ip4ip6_err()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nip6_tunnel: clear skb2->cb[] in ip4ip6_err()\n\nOskar Kjos reported the following problem.\n\nip4ip6_err() calls icmp_send() on a cloned skb whose cb[] was written\nby the IPv6 receive path as struct inet6_skb_parm. icmp_send() passes\nIPCB(skb2) to __ip_options_echo(), which interprets that cb[] region\nas struct inet_skb_parm (IPv4). The layouts differ: inet6_skb_parm.nhoff\nat offset 14 overlaps inet_skb_parm.opt.rr, producing a non-zero rr\nvalue. __ip_options_echo() then reads optlen from attacker-controlled\npacket data at sptr[rr+1] and copies that many bytes into dopt->__data,\na fixed 40-byte stack buffer (IP_OPTIONS_DATA_FIXED_SIZE).\n\nTo fix this we clear skb2->cb[], as suggested by Oskar Kjos.\n\nAlso add minimal IPv4 header validation (version == 4, ihl >= 5).","affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"c4d3efafcc933fd2ffd169d7dc4f980393a13796"},{"fixed":"ea9f65b27c8404e164848ebff1443310fd187629"},{"fixed":"d6621f60192fe10c047a4487be42a6f4c150707f"},{"fixed":"2cc6e3b0fe0f0242d1f530a93a4924f48ab85ba5"},{"fixed":"a0c4ce9900a108eaf55d0f3b399cb55999647d39"},{"fixed":"1063515ce15ff31065c4e7f8265f4c2fd3c54876"},{"fixed":"590f622669b97eaf7b57a1de7b0a6e68c5d8b2c3"},{"fixed":"4a622658f384b03560834cbe8ffcfe69a278f7c8"},{"fixed":"2edfa31769a4add828a7e604b21cb82aaaa05925"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43037.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.22"},{"fixed":"5.10.253"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.203"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.168"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.134"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.81"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.22"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.12"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43037.json"}}],"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1063515ce15ff31065c4e7f8265f4c2fd3c54876"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2cc6e3b0fe0f0242d1f530a93a4924f48ab85ba5"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2edfa31769a4add828a7e604b21cb82aaaa05925"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4a622658f384b03560834cbe8ffcfe69a278f7c8"},{"type":"WEB","url":"https://git.kernel.org/stable/c/590f622669b97eaf7b57a1de7b0a6e68c5d8b2c3"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a0c4ce9900a108eaf55d0f3b399cb55999647d39"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d6621f60192fe10c047a4487be42a6f4c150707f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ea9f65b27c8404e164848ebff1443310fd187629"},{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-43037.json"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:22900"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:22940"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:22964"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:23224"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:23237"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:24343"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:25120"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:25121"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:25181"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:25186"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:25191"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:25193"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:25200"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:25217"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:25533"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:25534"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:26528"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:26535"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:26542"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:27719"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:27729"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:28738"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:28740"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:28741"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:28742"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:28748"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:28749"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:28750"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:28887"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:28962"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:33486"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:34098"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:41236"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-43037"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cveli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