{"cve":"CVE-2026-31665","nvd":{"published":"2026-04-24T15:16:46.157","modified":"2026-10-19T19:18:04.190","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_ct: fix use-after-free in timeout object destroy\n\nnft_ct_timeout_obj_destroy() frees the timeout object with kfree()\nimmediately after nf_ct_untimeout(), without waiting for an RCU grace\nperiod. Concurrent packet processing on other CPUs may still hold\nRCU-protected references to the timeout object obtained via\nrcu_dereference() in nf_ct_timeout_data().\n\nAdd an rcu_head to struct nf_ct_timeout and use kfree_rcu() to defer\nfreeing until after an RCU grace period, matching the approach already\nused in nfnetlink_cttimeout.c.\n\nKASAN report:\n BUG: KASAN: slab-use-after-free in nf_conntrack_tcp_packet+0x1381/0x29d0\n Read of size 4 at addr ffff8881035fe19c by task exploit/80\n\n Call Trace:\n  nf_conntrack_tcp_packet+0x1381/0x29d0\n  nf_conntrack_in+0x612/0x8b0\n  nf_hook_slow+0x70/0x100\n  __ip_local_out+0x1b2/0x210\n  tcp_sendmsg_locked+0x722/0x1580\n  __sys_sendto+0x2d8/0x320\n\n Allocated by task 75:\n  nft_ct_timeout_obj_init+0xf6/0x290\n  nft_obj_init+0x107/0x1b0\n  nf_tables_newobj+0x680/0x9c0\n  nfnetlink_rcv_batch+0xc29/0xe00\n\n Freed by task 26:\n  nft_obj_destroy+0x3f/0xa0\n  nf_tables_trans_destroy_work+0x51c/0x5c0\n  process_one_work+0x2c4/0x5a0","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":["CWE-416"],"references":["https://git.kernel.org/stable/c/070abdf1b04325b21a20a2a0c39a2208af107275","https://git.kernel.org/stable/c/aa7cfa16f98f8ec3e6d47c34e1a8c1ae4b9b8b77","https://git.kernel.org/stable/c/b42aca3660dc2627a29a38131597ca610dc451f9","https://git.kernel.org/stable/c/c458fc1c278a65ad5381083121d39a479973ebed","https://git.kernel.org/stable/c/c581e5c8f2b59158f62efe61c1a3dc36189081ff"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-21T03:43:09.190223697+00:00"},"epss":{"cve":"CVE-2026-31665","score":0.00123,"percentile":0.02043,"date":"2026-10-26"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}