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High 7.8Published Oct 7, 2025

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

Updated under an hour ago ()

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It affects Linux and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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

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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.

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