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Vulnerabilities
Vulnerability

CVE-2026-43027

Reference data from vuln.mlab.sh, coverage from our own index.

CVSS
7.1 High
Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Risk score
56.8
Published
2026-05-01
Status
Published

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_helper: pass helper to expect cleanup nf_conntrack_helper_unregister() calls nf_ct_expect_iterate_destroy() to remove expectations belonging to the helper being unregistered. However, it passes NULL instead of the helper pointer as the data argument, so expect_iter_me() never matches any expectation and all of them survive the cleanup. After unregister returns, nfnl_cthelper_del() frees the helper object immediately. Subsequent expectation dumps or packet-driven init_conntrack() calls then dereference the freed exp->helper, causing a use-after-free. Pass the actual helper pointer so expectations referencing it are properly destroyed before the helper object is freed. BUG: KASAN: slab-use-after-free in string+0x38f/0x430 Read of size 1 at addr ffff888003b14d20 by task poc/103 Call Trace: string+0x38f/0x430 vsnprintf+0x3cc/0x1170 seq_printf+0x17a/0x240 exp_seq_show+0x2e5/0x560 seq_read_iter+0x419/0x1280 proc_reg_read+0x1ac/0x270 vfs_read+0x179/0x930 ksys_read+0xef/0x1c0 Freed by task 103: The buggy address is located 32 bytes inside of freed 192-byte region [ffff888003b14d00, ffff888003b14dc0) A flaw was found in the Linux kernel's netfilter subsystem, specifically within the `nf_conntrack_helper`. When a connection tracking helper is unregistered, its associated expectations are not properly cleaned up. This oversight can lead to a use-after-free vulnerability, where the system attempts to access memory that has already been released. A local attacker could exploit this to cause a system crash, resulting in a Denial of Service (DoS), or potentially achieve privilege escalation.

Weaknesses

CWE-459

Coverage 11

Advisories and references