CVE-2026-43450

CVE-2026-43450 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.

Key facts

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

Frequently asked questions

What is CVE-2026-43450?
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
How severe is CVE-2026-43450?
CVE-2026-43450 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.
Is CVE-2026-43450 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-43450?
CVE-2026-43450 primarily affects Linux Linux Kernel. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-43450?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-43450 have an EU (EUVD) identifier?
Yes. CVE-2026-43450 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-28756.
When was CVE-2026-43450 published?
CVE-2026-43450 was published on 2026-05-08 and last updated on 2026-06-17.

References

Affected products (4)

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