CVE-2023-53619
netfilter: conntrack: Avoid nf_ct_helper_hash uses after free
In the Linux kernel, the following vulnerability has been resolved: netfilter: conntrack: Avoid nf_ct_helper_hash uses after free If nf_conntrack_init_start() fails (for example due to a register_nf_conntrack_bpf() failure), the nf_conntrack_helper_fini() clean-up path frees the nf_ct_helper_hash map. When built with NF_CONNTRACK=y, further netfilter modules (e.g: netfilter_conntrack_ftp) can still be loaded and call nf_conntrack_helpers_register(), independently of whether nf_conntrack initialized correctly. This accesses the nf_ct_helper_hash dangling pointer and causes a uaf, possibly leading to random memory corruption. This patch guards nf_conntrack_helper_register() from accessing a freed or uninitialized nf_ct_helper_hash pointer and fixes possible uses-after-free when loading a conntrack module.
| Vendor | linux |
| Product | linux |
| Ecosystems | |
| Industries | Technology |
| Published | Oct 7, 2025 |
| Last Updated | May 11, 2026 |
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