{"id":"CVE-2026-23413","summary":"clsact: Fix use-after-free in init/destroy rollback asymmetry","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nclsact: Fix use-after-free in init/destroy rollback asymmetry\n\nFix a use-after-free in the clsact qdisc upon init/destroy rollback asymmetry.\nThe latter is achieved by first fully initializing a clsact instance, and\nthen in a second step having a replacement failure for the new clsact qdisc\ninstance. clsact_init() initializes ingress first and then takes care of the\negress part. This can fail midway, for example, via tcf_block_get_ext(). Upon\nfailure, the kernel will trigger the clsact_destroy() callback.\n\nCommit 1cb6f0bae504 (\"bpf: Fix too early release of tcx_entry\") details the\nway how the transition is happening. If tcf_block_get_ext on the q-\u003eingress_block\nends up failing, we took the tcx_miniq_inc reference count on the ingress\nside, but not yet on the egress side. clsact_destroy() tests whether the\n{ingress,egress}_entry was non-NULL. However, even in midway failure on the\nreplacement, both are in fact non-NULL with a valid egress_entry from the\nprevious clsact instance.\n\nWhat we really need to test for is whether the qdisc instance-specific ingress\nor egress side previously got initialized. This adds a small helper for checking\nthe miniq initialization called mini_qdisc_pair_inited, and utilizes that upon\nclsact_destroy() in order to fix the use-after-free scenario. Convert the\ningress_destroy() side as well so both are consistent to each other.","modified":"2026-04-14T03:47:56.830153Z","published":"2026-04-02T11:40:54.384Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23413.json","cna_assigner":"Linux"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/0509b762bc5e8ea7b8391130730c6d8502fc6e69"},{"type":"WEB","url":"https://git.kernel.org/stable/c/37bef86e5428d59f70a4da82b80f9a8f252fecbe"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4c9af67f99aa3e51b522c54968ab3ac8272be41c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a0671125d4f55e1e98d9bde8a0b671941987e208"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a73d95b57bf9faebdfed591bcb7ed9292062a84c"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23413.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23413"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"230bb13650b0f186f540500fd5f5f7096a822a2a"},{"fixed":"a73d95b57bf9faebdfed591bcb7ed9292062a84c"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"1cb6f0bae50441f4b4b32a28315853b279c7404e"},{"fixed":"37bef86e5428d59f70a4da82b80f9a8f252fecbe"},{"fixed":"4c9af67f99aa3e51b522c54968ab3ac8272be41c"},{"fixed":"0509b762bc5e8ea7b8391130730c6d8502fc6e69"},{"fixed":"a0671125d4f55e1e98d9bde8a0b671941987e208"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0"},{"last_affected":"f61ecf1bd5b562ebfd7d430ccb31619857e80857"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-23413.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.130"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.78"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.10.0"},{"fixed":"6.18.20"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.19.10"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-23413.json"}}],"schema_version":"1.7.5"}