Vulnerability in Linux

CVE-2026-53269

In the Linux kernel, the following vulnerability has been resolved: netfilter: synproxy: add mutex to guard hook reference counting As the synproxy infrastructure register netfilter hooks on-demand when a user adds the first iptables target or nftables expression, if done concurrently they can race each other. Introduce a mutex to serialize the refcount control blocks access from both frontends. While a per namespace mutex might be more efficient, it is not needed for target/expression like SYNPROXY.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.001 (1.5th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 1st percentile — 1.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-53269: held from 0.002 to 0.001.

EPSS over last 30 days · oldest: 0.002 · newest: 0.001 · change: -0.000

Affected products

  • Linux — versions ad49d86e07a497e834cb06f2b151dccd75f8e148, 5.3, 0
  • Linux Kernel — versions 7.1

References

Frequently asked questions

What is CVE-2026-53269?
CVE-2026-53269 is a medium-severity vulnerability in Linux. CVSS score: 5.5/10. Published 2026-06-25.
How severe is CVE-2026-53269?
Medium severity. CVSS v3 base score is 5.5 out of 10.