High 7.8Published Oct 7, 2025

CVE-2023-53619netfilter: conntrack: Avoid nf_ct_helper_hash uses after free

Updated under an hour ago (Oct 27, 2026, 3:30 PM ET)

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Exploited in the last 30 days

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.

CVSS: 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 15, 2026
First seen by InfoSec Signals: Oct 15, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	12f7a505331e6b2754684b509f2ac8f0011ce644 builds before 4ee69c91cb8f9ca144bc0861969e5a1a3c6152a7; from 12f7a505331e6b2754684b509f2ac8f0011ce644 before 00716f25f9697d02a0d9bd622575c7c7321ba3d0; from 12f7a505331e6b2754684b509f2ac8f0011ce644 before 61c7a5256543ae7d24cd9d21853d514c8632e1e9; from 12f7a505331e6b2754684b509f2ac8f0011ce644 before 8289d422f5e484efe4a565fe18e862ecd621c175; 12f7a505331e6b2754684b509f2ac8f0011ce644 builds before 6f03ce2f1abcb9f9d0511e3659ca6eb60e39f566; from 12f7a505331e6b2754684b509f2ac8f0011ce644 before 05561f822f27b9fa88fa5504ddec34bf38833034; from 12f7a505331e6b2754684b509f2ac8f0011ce644 before fce5cc7cbd4b92f979bf02c9ec5fb69aaeba92d7; 12f7a505331e6b2754684b509f2ac8f0011ce644 builds before 6eef7a2b933885a17679eb8ed0796ddf0ee5309b	CNA record
linux linux_kernel linux:linux_kernel	from 3.6 before 4.14.322; from 4.15 before 4.19.291; from 4.20 before 5.4.251; from 5.5 before 5.10.188; from 5.11 before 5.15.121; from 5.16 before 6.1.39; from 6.2 before 6.4.4; 6.5	NVD

References

References

https://git.kernel.org/stable/c/4ee69c91cb8f9ca144bc0861969e5a1a3c6152a7	patch
https://git.kernel.org/stable/c/00716f25f9697d02a0d9bd622575c7c7321ba3d0	patch
https://git.kernel.org/stable/c/61c7a5256543ae7d24cd9d21853d514c8632e1e9	patch
https://git.kernel.org/stable/c/8289d422f5e484efe4a565fe18e862ecd621c175	patch
https://git.kernel.org/stable/c/6f03ce2f1abcb9f9d0511e3659ca6eb60e39f566	patch
https://git.kernel.org/stable/c/05561f822f27b9fa88fa5504ddec34bf38833034	patch
https://git.kernel.org/stable/c/fce5cc7cbd4b92f979bf02c9ec5fb69aaeba92d7	patch
https://git.kernel.org/stable/c/6eef7a2b933885a17679eb8ed0796ddf0ee5309b	patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.