{"id":"CVE-2026-43026","summary":"netfilter: ctnetlink: zero expect NAT fields when CTA_EXPECT_NAT absent","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ctnetlink: zero expect NAT fields when CTA_EXPECT_NAT absent\n\nctnetlink_alloc_expect() allocates expectations from a non-zeroing\nslab cache via nf_ct_expect_alloc().  When CTA_EXPECT_NAT is not\npresent in the netlink message, saved_addr and saved_proto are\nnever initialized.  Stale data from a previous slab occupant can\nthen be dumped to userspace by ctnetlink_exp_dump_expect(), which\nchecks these fields to decide whether to emit CTA_EXPECT_NAT.\n\nThe safe sibling nf_ct_expect_init(), used by the packet path,\nexplicitly zeroes these fields.\n\nZero saved_addr, saved_proto and dir in the else branch, guarded\nby IS_ENABLED(CONFIG_NF_NAT) since these fields only exist when\nNAT is enabled.\n\nConfirmed by priming the expect slab with NAT-bearing expectations,\nfreeing them, creating a new expectation without CTA_EXPECT_NAT,\nand observing that the ctnetlink dump emits a spurious\nCTA_EXPECT_NAT containing stale data from the prior allocation.","modified":"2026-07-04T18:29:13.627533158Z","published":"2026-05-01T14:15:27.854Z","related":["SUSE-SU-2026:22099-1","SUSE-SU-2026:22108-1","SUSE-SU-2026:22112-1","SUSE-SU-2026:22127-1","SUSE-SU-2026:22137-1","SUSE-SU-2026:22433-1","SUSE-SU-2026:22458-1","SUSE-SU-2026:2450-1","SUSE-SU-2026:2482-1","SUSE-SU-2026:2591-1","openSUSE-SU-2026:20965-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43026.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1c2ebdeff8d088a2e47ae25d7b38447249adace2"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2898080c054ea4d6ddfaaf21bbedbc229a9a8376"},{"type":"WEB","url":"https://git.kernel.org/stable/c/35177c6877134a21315f37d57a5577846225623e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/929f7a9a7aad9404a5867216c3f8738232355b38"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a5a89db6981a1ddf2314bf50cb49db5a3146185f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a64b7bf84b4d5ea54218c5d374ec87fff9000f43"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bff0f4f06f12d6d9bc565a3e1378abd4f6f5ce36"},{"type":"WEB","url":"https://git.kernel.org/stable/c/fd002ff2ea030cbfb0188a11b3c60ce7f84485f4"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43026.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-43026"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"076a0ca02644657b13e4af363f487ced2942e9cb"},{"fixed":"a5a89db6981a1ddf2314bf50cb49db5a3146185f"},{"fixed":"1c2ebdeff8d088a2e47ae25d7b38447249adace2"},{"fixed":"a64b7bf84b4d5ea54218c5d374ec87fff9000f43"},{"fixed":"2898080c054ea4d6ddfaaf21bbedbc229a9a8376"},{"fixed":"fd002ff2ea030cbfb0188a11b3c60ce7f84485f4"},{"fixed":"929f7a9a7aad9404a5867216c3f8738232355b38"},{"fixed":"bff0f4f06f12d6d9bc565a3e1378abd4f6f5ce36"},{"fixed":"35177c6877134a21315f37d57a5577846225623e"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-43026.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.4.0"},{"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/osv-test-cve-osv-conversion/osv-output/CVE-2026-43026.json"}}],"schema_version":"1.7.5"}