CVE-2026-53269 | netfilter: synproxy: add mutex to guard hook reference counting

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: 2026-06-25 Last update: 2026-06-25 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Conclusion & alert: CVE-2026-53269 is rated Low Risk (6.8/100): low exploitation likelihood (EPSS 0.17%). Mandatory action: Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-53269

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-25 0.17%

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-53269

CVSS metrics for this CVE.

No CVSS data in dataset for this CVE.

Weakness enumeration for CVE-2026-53269

GitHub Security Advisory for CVE-2026-53269

GHSA-7m9q-85qj-rc4g · Severity: unknown — In the Linux kernel, the following vulnerability has been resolved: netfilter: synproxy: add...

OS Trackers for CVE-2026-53269

vendor priority summary link
debian not yet assigned CVE-2026-53269 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 3, resolved 2. https://security-tracker.debian.org/tracker/CVE-2026-53269
redhat medium https://access.redhat.com/security/cve/CVE-2026-53269
ubuntu medium CVE-2026-53269 medium priority: Ubuntu including 161 source packages (linux, linux-allwinner-5.19, …), 1449 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): DNE 1045, ignored 172, needed 119, released 87, not-affected 23, needs-triage 3. https://ubuntu.com/security/CVE-2026-53269

Affected software / configurations for CVE-2026-53269

Vendor Product Version Raw CPE
linux linux_kernel >= 5.3, < 5.10.259 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.3, < 5.15.210 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.3, < 6.1.176 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.3, < 6.6.143 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.3, < 6.12.94 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.3, < 6.18.36 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.3, < 7.0.13 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.3, < 7.1 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

References for CVE-2026-53269

cvelogic Threat Intelligence