CVE-2026-43450

HIGH

netfilter: nfnetlink_cthelper: fix OOB read in nfnl_cthelper_dump_table()

Title source: cna
STIX 2.1

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_cthelper: fix OOB read in nfnl_cthelper_dump_table() nfnl_cthelper_dump_table() has a 'goto restart' that jumps to a label inside the for loop body. When the "last" helper saved in cb->args[1] is deleted between dump rounds, every entry fails the (cur != last) check, so cb->args[1] is never cleared. The for loop finishes with cb->args[0] == nf_ct_helper_hsize, and the 'goto restart' jumps back into the loop body bypassing the bounds check, causing an 8-byte out-of-bounds read on nf_ct_helper_hash[nf_ct_helper_hsize]. The 'goto restart' block was meant to re-traverse the current bucket when "last" is no longer found, but it was placed after the for loop instead of inside it. Move the block into the for loop body so that the restart only occurs while cb->args[0] is still within bounds. BUG: KASAN: slab-out-of-bounds in nfnl_cthelper_dump_table+0x9f/0x1b0 Read of size 8 at addr ffff888104ca3000 by task poc_cthelper/131 Call Trace: nfnl_cthelper_dump_table+0x9f/0x1b0 netlink_dump+0x333/0x880 netlink_recvmsg+0x3e2/0x4b0 sock_recvmsg+0xde/0xf0 __sys_recvfrom+0x150/0x200 __x64_sys_recvfrom+0x76/0x90 do_syscall_64+0xc3/0x6e0 Allocated by task 1: __kvmalloc_node_noprof+0x21b/0x700 nf_ct_alloc_hashtable+0x65/0xd0 nf_conntrack_helper_init+0x21/0x60 nf_conntrack_init_start+0x18d/0x300 nf_conntrack_standalone_init+0x12/0xc0

Scores

CVSS v3 7.1
EPSS 0.0013
EPSS Percentile 3.1%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Details

CWE
CWE-125
Status published
Products (27)
linux/Kernel 3.6.0 - 5.10.253linux
linux/Kernel 5.11.0 - 5.15.203linux
linux/Kernel 5.16.0 - 6.1.167linux
linux/Kernel 6.13.0 - 6.18.19linux
linux/Kernel 6.19.0 - 6.19.9linux
linux/Kernel 6.2.0 - 6.6.130linux
linux/Kernel 6.7.0 - 6.12.78linux
Linux/Linux < 3.6
Linux/Linux 12f7a505331e6b2754684b509f2ac8f0011ce644 - 05018cd9370f77bb18fbf6e15ff33c7a06f10b3c
Linux/Linux 12f7a505331e6b2754684b509f2ac8f0011ce644 - 0605e1985a95d4334a67869aee45a47e82301abf
... and 17 more
Published May 08, 2026
Tracked Since May 08, 2026