{"id":"CVE-2026-74740","title":"net/sched: act_api: fix TOCTOU NULL deref on a->goto_chain","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: act_api: fix TOCTOU NULL deref on a->goto_chain\n\ntcf_action_exec() handles TC_ACT_GOTO_CHAIN by first checking\nrcu_access_pointer(a->goto_chain) and then cal…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 < 28aa0c9dd0b1b38436995d4c15621ad3f896c7e3","Linux >= ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 < 91d55fd1fdb85c8371ca8793c788ea7d5192383a","Linux >= ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 < 1ec48b6715c29b20105e3485206602cff6c51ae5","Linux >= ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 < abceabc4408fca6a9dd52611f5d197dec9390d63","Linux >= ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 < 6b70886ebc428eed43a069c8944a931b5fb3f4e4","Linux >= ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 < f60b396ee174206fe08ebf997d16cd3801b77b22","Linux 5.1"],"published":"2026-08-26","updated":"2026-10-30","sourceUpdated":"2026-10-30T12:30:29.380Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-74740","references":[{"url":"https://git.kernel.org/stable/c/28aa0c9dd0b1b38436995d4c15621ad3f896c7e3"},{"url":"https://git.kernel.org/stable/c/91d55fd1fdb85c8371ca8793c788ea7d5192383a"},{"url":"https://git.kernel.org/stable/c/1ec48b6715c29b20105e3485206602cff6c51ae5"},{"url":"https://git.kernel.org/stable/c/abceabc4408fca6a9dd52611f5d197dec9390d63"},{"url":"https://git.kernel.org/stable/c/6b70886ebc428eed43a069c8944a931b5fb3f4e4"},{"url":"https://git.kernel.org/stable/c/f60b396ee174206fe08ebf997d16cd3801b77b22"}],"tags":["cve.org"],"epss":0.00181,"epssPercentile":0.07708,"ingestedAt":"2026-11-05T15:02:32.579Z","slug":"CVE-2026-74740","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: act_api: fix TOCTOU NULL deref on a->goto_chain\n\ntcf_action_exec() handles TC_ACT_GOTO_CHAIN by first checking\nrcu_access_pointer(a->goto_chain) and then calling\ntcf_action_goto_chain_exec(), which does a second, independent\nrcu_dereference_bh(a->goto_chain) read and immediately dereferences\nchain->filter_chain. A concurrent tcf_action_set_ctrlact() (e.g. the gact\nreplace path) can clear a->goto_chain between the two reads, so the second\nread returns NULL and tcf_action_goto_chain_exec() dereferences NULL.\n\nFix the race by doing a single rcu_dereference_bh() read of a->goto_chain\nin tcf_action_exec(), checking it once for NULL, and passing the resulting\nchain pointer into tcf_action_goto_chain_exec(). This turns the split\ncheck/use into a single check/use on one value.\n\n## Affected\n\n- `Linux >= ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 < 28aa0c9dd0b1b38436995d4c15621ad3f896c7e3`\n- `Linux >= ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 < 91d55fd1fdb85c8371ca8793c788ea7d5192383a`\n- `Linux >= ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 < 1ec48b6715c29b20105e3485206602cff6c51ae5`\n- `Linux >= ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 < abceabc4408fca6a9dd52611f5d197dec9390d63`\n- `Linux >= ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 < 6b70886ebc428eed43a069c8944a931b5fb3f4e4`\n- `Linux >= ee3bbfe806cdb46b02cda63626cb50a7a7b19fc5 < f60b396ee174206fe08ebf997d16cd3801b77b22`\n- `Linux 5.1`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}