{"api_version":"1","generated_at":"2026-09-18T05:19:08+00:00","cve":"CVE-2026-90078","urls":{"html":"https://cve.report/CVE-2026-90078","api":"https://cve.report/api/cve/CVE-2026-90078.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-90078","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-90078"},"summary":{"title":"net/sched: act_skbmod: fix length calculations and avoid invalid header warnings","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: act_skbmod: fix length calculations and avoid invalid header warnings\n\nsyzbot reported a warning in skb_network_header_len() triggered\nby tcf_skbmod_act():\n\n  !skb_transport_header_was_set(skb)\n  WARNING: CPU: 0 PID: 14949 at include/linux/skbuff.h:3243 skb_network_header_len include/linux/skbuff.h:3243 [inline]\n  WARNING: CPU: 0 PID: 14949 at net/sched/act_skbmod.c:55 tcf_skbmod_act+0xfe8/0x1810 net/sched/act_skbmod.c:55\n\nThere are a few issues in tcf_skbmod_act():\n\n1. Calling skb_network_header_len() assumes skb->transport_header is set,\n   which is not guaranteed when tcf_skbmod_act() runs at TC ingress.\n2. Unconditionally calling skb_mac_header_len() at the beginning of\n   tcf_skbmod_act() triggers a warning on L3 devices (e.g. TUN) where the\n   MAC header is unset, evaluating to an underflowed garbage length.\n3. On TC ingress, skb->data points to the network header. Adding the MAC\n   header length to the IP header length causes skb_ensure_writable() to\n   request more bytes than the actual IP packet length, dropping valid\n   short packets (e.g. 28-byte UDP/IPv4 packets).\n\nFix these by:\n- Using skb_network_offset(skb) + sizeof(struct iphdr/ipv6hdr) for\n  SKBMOD_F_ECN so that the required length is correctly calculated on\n  both ingress (offset == 0) and egress (offset == mac_len).\n- Setting max_edit_len to ETH_HLEN for Ethernet header modifications\n  after validating ARPHRD_ETHER.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-17 17:16:57","updated_at":"2026-09-17 17:16:57"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/e8a2027b7e686784a69b2dfcee841d779919f313","name":"https://git.kernel.org/stable/c/e8a2027b7e686784a69b2dfcee841d779919f313","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/62126464f3a6159c0a3dd89e196ba65bfeb0afc6","name":"https://git.kernel.org/stable/c/62126464f3a6159c0a3dd89e196ba65bfeb0afc6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d896843d8d925f0adbba319020595cfb1a7bcd57","name":"https://git.kernel.org/stable/c/d896843d8d925f0adbba319020595cfb1a7bcd57","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1719865b20b22c88d2a55e922eff5ca31b0841f6","name":"https://git.kernel.org/stable/c/1719865b20b22c88d2a55e922eff5ca31b0841f6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/81d0d1e64f30d9989c829c0953cd6e6c68d9c5fb","name":"https://git.kernel.org/stable/c/81d0d1e64f30d9989c829c0953cd6e6c68d9c5fb","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0675cff3c2924eb9b80d9dd250cf56a1140af157","name":"https://git.kernel.org/stable/c/0675cff3c2924eb9b80d9dd250cf56a1140af157","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/985a37781ade19061400100c2ba0f43979dd4d63","name":"https://git.kernel.org/stable/c/985a37781ade19061400100c2ba0f43979dd4d63","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-90078","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90078","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 56af5e749f20c3a540310c207dcc373f4f09156e 985a37781ade19061400100c2ba0f43979dd4d63 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 56af5e749f20c3a540310c207dcc373f4f09156e d896843d8d925f0adbba319020595cfb1a7bcd57 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 56af5e749f20c3a540310c207dcc373f4f09156e 0675cff3c2924eb9b80d9dd250cf56a1140af157 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 56af5e749f20c3a540310c207dcc373f4f09156e e8a2027b7e686784a69b2dfcee841d779919f313 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 56af5e749f20c3a540310c207dcc373f4f09156e 1719865b20b22c88d2a55e922eff5ca31b0841f6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 56af5e749f20c3a540310c207dcc373f4f09156e 62126464f3a6159c0a3dd89e196ba65bfeb0afc6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 56af5e749f20c3a540310c207dcc373f4f09156e 81d0d1e64f30d9989c829c0953cd6e6c68d9c5fb git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.15","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.221 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.188 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.157 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.110 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.52 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.6 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/sched/act_skbmod.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"985a37781ade19061400100c2ba0f43979dd4d63","status":"affected","version":"56af5e749f20c3a540310c207dcc373f4f09156e","versionType":"git"},{"lessThan":"d896843d8d925f0adbba319020595cfb1a7bcd57","status":"affected","version":"56af5e749f20c3a540310c207dcc373f4f09156e","versionType":"git"},{"lessThan":"0675cff3c2924eb9b80d9dd250cf56a1140af157","status":"affected","version":"56af5e749f20c3a540310c207dcc373f4f09156e","versionType":"git"},{"lessThan":"e8a2027b7e686784a69b2dfcee841d779919f313","status":"affected","version":"56af5e749f20c3a540310c207dcc373f4f09156e","versionType":"git"},{"lessThan":"1719865b20b22c88d2a55e922eff5ca31b0841f6","status":"affected","version":"56af5e749f20c3a540310c207dcc373f4f09156e","versionType":"git"},{"lessThan":"62126464f3a6159c0a3dd89e196ba65bfeb0afc6","status":"affected","version":"56af5e749f20c3a540310c207dcc373f4f09156e","versionType":"git"},{"lessThan":"81d0d1e64f30d9989c829c0953cd6e6c68d9c5fb","status":"affected","version":"56af5e749f20c3a540310c207dcc373f4f09156e","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/sched/act_skbmod.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.15"},{"lessThan":"5.15","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.221","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.188","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.157","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.110","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.52","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.6","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.221","versionStartIncluding":"5.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.188","versionStartIncluding":"5.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.157","versionStartIncluding":"5.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.110","versionStartIncluding":"5.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.52","versionStartIncluding":"5.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.6","versionStartIncluding":"5.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc1","versionStartIncluding":"5.15","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: act_skbmod: fix length calculations and avoid invalid header warnings\n\nsyzbot reported a warning in skb_network_header_len() triggered\nby tcf_skbmod_act():\n\n  !skb_transport_header_was_set(skb)\n  WARNING: CPU: 0 PID: 14949 at include/linux/skbuff.h:3243 skb_network_header_len include/linux/skbuff.h:3243 [inline]\n  WARNING: CPU: 0 PID: 14949 at net/sched/act_skbmod.c:55 tcf_skbmod_act+0xfe8/0x1810 net/sched/act_skbmod.c:55\n\nThere are a few issues in tcf_skbmod_act():\n\n1. Calling skb_network_header_len() assumes skb->transport_header is set,\n   which is not guaranteed when tcf_skbmod_act() runs at TC ingress.\n2. Unconditionally calling skb_mac_header_len() at the beginning of\n   tcf_skbmod_act() triggers a warning on L3 devices (e.g. TUN) where the\n   MAC header is unset, evaluating to an underflowed garbage length.\n3. On TC ingress, skb->data points to the network header. Adding the MAC\n   header length to the IP header length causes skb_ensure_writable() to\n   request more bytes than the actual IP packet length, dropping valid\n   short packets (e.g. 28-byte UDP/IPv4 packets).\n\nFix these by:\n- Using skb_network_offset(skb) + sizeof(struct iphdr/ipv6hdr) for\n  SKBMOD_F_ECN so that the required length is correctly calculated on\n  both ingress (offset == 0) and egress (offset == mac_len).\n- Setting max_edit_len to ETH_HLEN for Ethernet header modifications\n  after validating ARPHRD_ETHER."}],"providerMetadata":{"dateUpdated":"2026-09-17T16:05:56.878Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/985a37781ade19061400100c2ba0f43979dd4d63"},{"url":"https://git.kernel.org/stable/c/d896843d8d925f0adbba319020595cfb1a7bcd57"},{"url":"https://git.kernel.org/stable/c/0675cff3c2924eb9b80d9dd250cf56a1140af157"},{"url":"https://git.kernel.org/stable/c/e8a2027b7e686784a69b2dfcee841d779919f313"},{"url":"https://git.kernel.org/stable/c/1719865b20b22c88d2a55e922eff5ca31b0841f6"},{"url":"https://git.kernel.org/stable/c/62126464f3a6159c0a3dd89e196ba65bfeb0afc6"},{"url":"https://git.kernel.org/stable/c/81d0d1e64f30d9989c829c0953cd6e6c68d9c5fb"}],"title":"net/sched: act_skbmod: fix length calculations and avoid invalid header warnings","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-90078","datePublished":"2026-09-17T16:05:56.878Z","dateReserved":"2026-09-11T19:38:34.785Z","dateUpdated":"2026-09-17T16:05:56.878Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-17 17:16:57","lastModifiedDate":"2026-09-17 17:16:57","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"90078","Ordinal":"1","Title":"net/sched: act_skbmod: fix length calculations and avoid invalid","CVE":"CVE-2026-90078","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"90078","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: act_skbmod: fix length calculations and avoid invalid header warnings\n\nsyzbot reported a warning in skb_network_header_len() triggered\nby tcf_skbmod_act():\n\n  !skb_transport_header_was_set(skb)\n  WARNING: CPU: 0 PID: 14949 at include/linux/skbuff.h:3243 skb_network_header_len include/linux/skbuff.h:3243 [inline]\n  WARNING: CPU: 0 PID: 14949 at net/sched/act_skbmod.c:55 tcf_skbmod_act+0xfe8/0x1810 net/sched/act_skbmod.c:55\n\nThere are a few issues in tcf_skbmod_act():\n\n1. Calling skb_network_header_len() assumes skb->transport_header is set,\n   which is not guaranteed when tcf_skbmod_act() runs at TC ingress.\n2. Unconditionally calling skb_mac_header_len() at the beginning of\n   tcf_skbmod_act() triggers a warning on L3 devices (e.g. TUN) where the\n   MAC header is unset, evaluating to an underflowed garbage length.\n3. On TC ingress, skb->data points to the network header. Adding the MAC\n   header length to the IP header length causes skb_ensure_writable() to\n   request more bytes than the actual IP packet length, dropping valid\n   short packets (e.g. 28-byte UDP/IPv4 packets).\n\nFix these by:\n- Using skb_network_offset(skb) + sizeof(struct iphdr/ipv6hdr) for\n  SKBMOD_F_ECN so that the required length is correctly calculated on\n  both ingress (offset == 0) and egress (offset == mac_len).\n- Setting max_edit_len to ETH_HLEN for Ethernet header modifications\n  after validating ARPHRD_ETHER.","Type":"Description","Title":"net/sched: act_skbmod: fix length calculations and avoid invalid"}]}}}