{"api_version":"1","generated_at":"2026-08-23T21:53:22+00:00","cve":"CVE-2026-74620","urls":{"html":"https://cve.report/CVE-2026-74620","api":"https://cve.report/api/cve/CVE-2026-74620.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-74620","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74620"},"summary":{"title":"net/sched: act_gact, act_police: range check the fallback control action","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: act_gact, act_police: range check the fallback control action\n\ntcf_action_check_ctrlact() range checks the primary control action:\n\n\tif (!opcode)\n\t\tret = action > TC_ACT_VALUE_MAX ? -EINVAL : 0;\n\nTC_ACT_VALUE_MAX is TC_ACT_TRAP, so kernel-internal verdicts above it\ncannot be set that way. But act_gact and act_police each carry a second,\nindependent control action supplied by user space that never reaches that\nhelper - TCA_GACT_PROB.paction and TCA_POLICE_RESULT. Both only reject\nTC_ACT_GOTO_CHAIN, so any other value is stored verbatim and returned\nverbatim from the action.\n\nIn particular user space can store TC_ACT_CONSUMED, which is\nTC_ACT_VALUE_MAX + 1 and is deliberately not part of the UAPI value\nrange. That verdict tells every caller the action took ownership of the\nskb, so nobody frees it: sch_handle_ingress(), sch_handle_egress() and\ntcf_qevent_handle() all deliberately skip the free for it. The result is\none leaked sk_buff plus its data buffer per packet traversing the filter,\nunbounded, for all traffic on the chain including kernel-generated\npackets.\n\nBoth are trivially deterministic. act_gact clamps tcfg_pval to >= 1, so\nwith pval = 1 gact_determ() returns the fallback for every packet.\nact_police has no mandatory rate, so rate = 0 leaves tcfp_mtu = ~0 and\ntcf_police_mtu_check() always passes.\n\nTC_ACT_CONSUMED was added by commit 720f22fed81b (\"net: sched: refactor\nreinsert action\"), after both goto-chain guards were written:\ncommit 9469f375ab09 (\"net/sched: act_gact: disallow 'goto chain' on\nfallback control action\") and\ncommit c08f5ed5d625 (\"net/sched: act_police: disallow 'goto chain' on\nfallback control action\"). Neither guard was widened when the new\nverdict appeared.\n\nFactor the existing range test out of tcf_action_check_ctrlact() as\ntcf_action_valid() and apply it to both fallbacks. The helper cannot call\ntcf_action_check_ctrlact() directly because that also allocates a\ngoto_chain, which is exactly what these two sites must not do.\n\nReproduced on v7.2-rc6: kmemleak reports one leaked 232-byte\nskbuff_head_cache object plus its 704-byte data buffer per packet. With\nthis patch both configurations are rejected with -EINVAL and kmemleak\nreports none.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-22 16:16:34","updated_at":"2026-08-23 13:16:47"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/efa58aeb6a99028b1fbc3ab2f31ba3a881211ad4","name":"https://git.kernel.org/stable/c/efa58aeb6a99028b1fbc3ab2f31ba3a881211ad4","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/6bcb8839aa2d686964a4154650afc4db91e1c514","name":"https://git.kernel.org/stable/c/6bcb8839aa2d686964a4154650afc4db91e1c514","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/92f00f1d4d204a428b38e26fce3baee144b6955d","name":"https://git.kernel.org/stable/c/92f00f1d4d204a428b38e26fce3baee144b6955d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/725efc2ab4a40affc4e285a2dc4896d103948a6c","name":"https://git.kernel.org/stable/c/725efc2ab4a40affc4e285a2dc4896d103948a6c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2e8df8c9190335475a3b64a159d3efd8cdd1cb73","name":"https://git.kernel.org/stable/c/2e8df8c9190335475a3b64a159d3efd8cdd1cb73","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/883b56ae58fe657d8497806c7059646e9ba6dbd0","name":"https://git.kernel.org/stable/c/883b56ae58fe657d8497806c7059646e9ba6dbd0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/5f038affdacaffedf6a85a06cf59ec0a852d36a7","name":"https://git.kernel.org/stable/c/5f038affdacaffedf6a85a06cf59ec0a852d36a7","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/5344e01179baa37547ab29fd7b8614f83faa190c","name":"https://git.kernel.org/stable/c/5344e01179baa37547ab29fd7b8614f83faa190c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-74620","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74620","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 720f22fed81bc6fd1765db7014651b6718887bea 5f038affdacaffedf6a85a06cf59ec0a852d36a7 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 720f22fed81bc6fd1765db7014651b6718887bea efa58aeb6a99028b1fbc3ab2f31ba3a881211ad4 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 720f22fed81bc6fd1765db7014651b6718887bea 725efc2ab4a40affc4e285a2dc4896d103948a6c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 720f22fed81bc6fd1765db7014651b6718887bea 6bcb8839aa2d686964a4154650afc4db91e1c514 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 720f22fed81bc6fd1765db7014651b6718887bea 5344e01179baa37547ab29fd7b8614f83faa190c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 720f22fed81bc6fd1765db7014651b6718887bea 92f00f1d4d204a428b38e26fce3baee144b6955d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 720f22fed81bc6fd1765db7014651b6718887bea 2e8df8c9190335475a3b64a159d3efd8cdd1cb73 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 720f22fed81bc6fd1765db7014651b6718887bea 883b56ae58fe657d8497806c7059646e9ba6dbd0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.3","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.3 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.10.266 5.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.216 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.183 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.152 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.104 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.45 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.9 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * 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":["include/net/act_api.h","net/sched/act_gact.c","net/sched/act_police.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"5f038affdacaffedf6a85a06cf59ec0a852d36a7","status":"affected","version":"720f22fed81bc6fd1765db7014651b6718887bea","versionType":"git"},{"lessThan":"efa58aeb6a99028b1fbc3ab2f31ba3a881211ad4","status":"affected","version":"720f22fed81bc6fd1765db7014651b6718887bea","versionType":"git"},{"lessThan":"725efc2ab4a40affc4e285a2dc4896d103948a6c","status":"affected","version":"720f22fed81bc6fd1765db7014651b6718887bea","versionType":"git"},{"lessThan":"6bcb8839aa2d686964a4154650afc4db91e1c514","status":"affected","version":"720f22fed81bc6fd1765db7014651b6718887bea","versionType":"git"},{"lessThan":"5344e01179baa37547ab29fd7b8614f83faa190c","status":"affected","version":"720f22fed81bc6fd1765db7014651b6718887bea","versionType":"git"},{"lessThan":"92f00f1d4d204a428b38e26fce3baee144b6955d","status":"affected","version":"720f22fed81bc6fd1765db7014651b6718887bea","versionType":"git"},{"lessThan":"2e8df8c9190335475a3b64a159d3efd8cdd1cb73","status":"affected","version":"720f22fed81bc6fd1765db7014651b6718887bea","versionType":"git"},{"lessThan":"883b56ae58fe657d8497806c7059646e9ba6dbd0","status":"affected","version":"720f22fed81bc6fd1765db7014651b6718887bea","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["include/net/act_api.h","net/sched/act_gact.c","net/sched/act_police.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.3"},{"lessThan":"5.3","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.266","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.216","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.183","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.152","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.104","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.45","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.9","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.266","versionStartIncluding":"5.3","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.216","versionStartIncluding":"5.3","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.183","versionStartIncluding":"5.3","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.152","versionStartIncluding":"5.3","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.104","versionStartIncluding":"5.3","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.45","versionStartIncluding":"5.3","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.9","versionStartIncluding":"5.3","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"5.3","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: act_gact, act_police: range check the fallback control action\n\ntcf_action_check_ctrlact() range checks the primary control action:\n\n\tif (!opcode)\n\t\tret = action > TC_ACT_VALUE_MAX ? -EINVAL : 0;\n\nTC_ACT_VALUE_MAX is TC_ACT_TRAP, so kernel-internal verdicts above it\ncannot be set that way. But act_gact and act_police each carry a second,\nindependent control action supplied by user space that never reaches that\nhelper - TCA_GACT_PROB.paction and TCA_POLICE_RESULT. Both only reject\nTC_ACT_GOTO_CHAIN, so any other value is stored verbatim and returned\nverbatim from the action.\n\nIn particular user space can store TC_ACT_CONSUMED, which is\nTC_ACT_VALUE_MAX + 1 and is deliberately not part of the UAPI value\nrange. That verdict tells every caller the action took ownership of the\nskb, so nobody frees it: sch_handle_ingress(), sch_handle_egress() and\ntcf_qevent_handle() all deliberately skip the free for it. The result is\none leaked sk_buff plus its data buffer per packet traversing the filter,\nunbounded, for all traffic on the chain including kernel-generated\npackets.\n\nBoth are trivially deterministic. act_gact clamps tcfg_pval to >= 1, so\nwith pval = 1 gact_determ() returns the fallback for every packet.\nact_police has no mandatory rate, so rate = 0 leaves tcfp_mtu = ~0 and\ntcf_police_mtu_check() always passes.\n\nTC_ACT_CONSUMED was added by commit 720f22fed81b (\"net: sched: refactor\nreinsert action\"), after both goto-chain guards were written:\ncommit 9469f375ab09 (\"net/sched: act_gact: disallow 'goto chain' on\nfallback control action\") and\ncommit c08f5ed5d625 (\"net/sched: act_police: disallow 'goto chain' on\nfallback control action\"). Neither guard was widened when the new\nverdict appeared.\n\nFactor the existing range test out of tcf_action_check_ctrlact() as\ntcf_action_valid() and apply it to both fallbacks. The helper cannot call\ntcf_action_check_ctrlact() directly because that also allocates a\ngoto_chain, which is exactly what these two sites must not do.\n\nReproduced on v7.2-rc6: kmemleak reports one leaked 232-byte\nskbuff_head_cache object plus its 704-byte data buffer per packet. With\nthis patch both configurations are rejected with -EINVAL and kmemleak\nreports none."}],"providerMetadata":{"dateUpdated":"2026-08-23T12:47:46.379Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/5f038affdacaffedf6a85a06cf59ec0a852d36a7"},{"url":"https://git.kernel.org/stable/c/efa58aeb6a99028b1fbc3ab2f31ba3a881211ad4"},{"url":"https://git.kernel.org/stable/c/725efc2ab4a40affc4e285a2dc4896d103948a6c"},{"url":"https://git.kernel.org/stable/c/6bcb8839aa2d686964a4154650afc4db91e1c514"},{"url":"https://git.kernel.org/stable/c/5344e01179baa37547ab29fd7b8614f83faa190c"},{"url":"https://git.kernel.org/stable/c/92f00f1d4d204a428b38e26fce3baee144b6955d"},{"url":"https://git.kernel.org/stable/c/2e8df8c9190335475a3b64a159d3efd8cdd1cb73"},{"url":"https://git.kernel.org/stable/c/883b56ae58fe657d8497806c7059646e9ba6dbd0"}],"title":"net/sched: act_gact, act_police: range check the fallback control action","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-74620","datePublished":"2026-08-22T15:32:04.254Z","dateReserved":"2026-08-15T05:44:03.921Z","dateUpdated":"2026-08-23T12:47:46.379Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-22 16:16:34","lastModifiedDate":"2026-08-23 13:16:47","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"74620","Ordinal":"1","Title":"net/sched: act_gact, act_police: range check the fallback contro","CVE":"CVE-2026-74620","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"74620","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: act_gact, act_police: range check the fallback control action\n\ntcf_action_check_ctrlact() range checks the primary control action:\n\n\tif (!opcode)\n\t\tret = action > TC_ACT_VALUE_MAX ? -EINVAL : 0;\n\nTC_ACT_VALUE_MAX is TC_ACT_TRAP, so kernel-internal verdicts above it\ncannot be set that way. But act_gact and act_police each carry a second,\nindependent control action supplied by user space that never reaches that\nhelper - TCA_GACT_PROB.paction and TCA_POLICE_RESULT. Both only reject\nTC_ACT_GOTO_CHAIN, so any other value is stored verbatim and returned\nverbatim from the action.\n\nIn particular user space can store TC_ACT_CONSUMED, which is\nTC_ACT_VALUE_MAX + 1 and is deliberately not part of the UAPI value\nrange. That verdict tells every caller the action took ownership of the\nskb, so nobody frees it: sch_handle_ingress(), sch_handle_egress() and\ntcf_qevent_handle() all deliberately skip the free for it. The result is\none leaked sk_buff plus its data buffer per packet traversing the filter,\nunbounded, for all traffic on the chain including kernel-generated\npackets.\n\nBoth are trivially deterministic. act_gact clamps tcfg_pval to >= 1, so\nwith pval = 1 gact_determ() returns the fallback for every packet.\nact_police has no mandatory rate, so rate = 0 leaves tcfp_mtu = ~0 and\ntcf_police_mtu_check() always passes.\n\nTC_ACT_CONSUMED was added by commit 720f22fed81b (\"net: sched: refactor\nreinsert action\"), after both goto-chain guards were written:\ncommit 9469f375ab09 (\"net/sched: act_gact: disallow 'goto chain' on\nfallback control action\") and\ncommit c08f5ed5d625 (\"net/sched: act_police: disallow 'goto chain' on\nfallback control action\"). Neither guard was widened when the new\nverdict appeared.\n\nFactor the existing range test out of tcf_action_check_ctrlact() as\ntcf_action_valid() and apply it to both fallbacks. The helper cannot call\ntcf_action_check_ctrlact() directly because that also allocates a\ngoto_chain, which is exactly what these two sites must not do.\n\nReproduced on v7.2-rc6: kmemleak reports one leaked 232-byte\nskbuff_head_cache object plus its 704-byte data buffer per packet. With\nthis patch both configurations are rejected with -EINVAL and kmemleak\nreports none.","Type":"Description","Title":"net/sched: act_gact, act_police: range check the fallback contro"}]}}}