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CVE-2026-31665— netfilter: nft_ct: fix use-after-free in timeout object destroy

CVSS 7.8 · High EPSS 0.01% · P2
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I. Basic Information for CVE-2026-31665

Vulnerability Information
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Vulnerability Title
netfilter: nft_ct: fix use-after-free in timeout object destroy
Source: NVD (National Vulnerability Database)
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_ct: fix use-after-free in timeout object destroy nft_ct_timeout_obj_destroy() frees the timeout object with kfree() immediately after nf_ct_untimeout(), without waiting for an RCU grace period. Concurrent packet processing on other CPUs may still hold RCU-protected references to the timeout object obtained via rcu_dereference() in nf_ct_timeout_data(). Add an rcu_head to struct nf_ct_timeout and use kfree_rcu() to defer freeing until after an RCU grace period, matching the approach already used in nfnetlink_cttimeout.c. KASAN report: BUG: KASAN: slab-use-after-free in nf_conntrack_tcp_packet+0x1381/0x29d0 Read of size 4 at addr ffff8881035fe19c by task exploit/80 Call Trace: nf_conntrack_tcp_packet+0x1381/0x29d0 nf_conntrack_in+0x612/0x8b0 nf_hook_slow+0x70/0x100 __ip_local_out+0x1b2/0x210 tcp_sendmsg_locked+0x722/0x1580 __sys_sendto+0x2d8/0x320 Allocated by task 75: nft_ct_timeout_obj_init+0xf6/0x290 nft_obj_init+0x107/0x1b0 nf_tables_newobj+0x680/0x9c0 nfnetlink_rcv_batch+0xc29/0xe00 Freed by task 26: nft_obj_destroy+0x3f/0xa0 nf_tables_trans_destroy_work+0x51c/0x5c0 process_one_work+0x2c4/0x5a0
Source: NVD (National Vulnerability Database)
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: NVD (National Vulnerability Database)
Vulnerability Type
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于nft_ct中超时对象释放后重用，可能导致内存损坏。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

VendorProductAffected VersionsCPESubscribe
LinuxLinux 7e0b2b57f01d183e1c84114f1f2287737358d748 ~ c458fc1c278a65ad5381083121d39a479973ebed -
LinuxLinux 4.19 -

II. Public POCs for CVE-2026-31665

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III. Intelligence Information for CVE-2026-31665

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Same Patch Batch · Linux · 2026-04-24 · 138 CVEs total

CVE-2026-316379.8 CRITICALrxrpc: reject undecryptable rxkad response tickets
CVE-2026-315369.8 CRITICALsmb: server: let send_done handle a completion without IB_SEND_SIGNALED
CVE-2026-315899.8 CRITICALmm: call ->free_folio() directly in folio_unmap_invalidate()
CVE-2026-316699.8 CRITICALmptcp: fix slab-use-after-free in __inet_lookup_established
CVE-2026-316689.8 CRITICALseg6: separate dst_cache for input and output paths in seg6 lwtunnel
CVE-2026-316499.8 CRITICALnet: stmmac: fix integer underflow in chain mode
CVE-2026-316339.8 CRITICALrxrpc: Fix integer overflow in rxgk_verify_response()
CVE-2026-316079.8 CRITICALusbip: validate number_of_packets in usbip_pack_ret_submit()
CVE-2026-316089.8 CRITICALsmb: server: avoid double-free in smb_direct_free_sendmsg after smb_direct_flush_send_list
CVE-2026-316099.8 CRITICALsmb: client: avoid double-free in smbd_free_send_io() after smbd_send_batch_flush()
CVE-2026-316579.8 CRITICALbatman-adv: hold claim backbone gateways by reference
CVE-2026-316599.8 CRITICALbatman-adv: reject oversized global TT response buffers
CVE-2026-316369.1 CRITICALrxrpc: fix RESPONSE authenticator parser OOB read
CVE-2026-315888.8 HIGHKVM: x86: Use scratch field in MMIO fragment to hold small write values
CVE-2026-315708.8 HIGHcan: gw: fix OOB heap access in cgw_csum_crc8_rel()
CVE-2026-316228.8 HIGHNFC: digital: Bounds check NFC-A cascade depth in SDD response handler
CVE-2026-315588.8 HIGHLoongArch: KVM: Make kvm_get_vcpu_by_cpuid() more robust
CVE-2026-315538.8 HIGHKVM: arm64: Fix the descriptor address in __kvm_at_swap_desc()
CVE-2026-316298.8 HIGHnfc: llcp: add missing return after LLCP_CLOSED checks
CVE-2026-316118.6 HIGHksmbd: require 3 sub-authorities before reading sub_auth[2]

Showing top 20 of 138 CVEs. View all on vendor page → →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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