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Advisory severityHigh7.1Vendor: MediumRed Hat Linux

High [CVE-2026-53236] restrict SO_ATTACH_FILTER to priv users

This high-severity Red Hat Linux advisory covers CVE-2026-53236 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-53236 Source published Source updated

VulniPulse record published Record updated

CVE-2026-53236
Affected products & platforms
Red Hat LinuxLinux Kernel
Open source advisory

Summary

In the Linux kernel, the following vulnerability has been resolved: tcp: restrict SO_ATTACH_FILTER to priv users This patch restricts the use of SO_ATTACH_FILTER (cBPF) on TCP sockets to users with CAP_NET_ADMIN capability.

This blocks potential side-channel attack where an unprivileged application attaches a filter to leak TCP sequence/acknowledgment numbers. An unprivileged application can exploit this vulnerability by attaching a Berkeley Packet Filter (BPF) using the SO_ATTACH_FILTER option.

This allows the application to conduct a side-channel attack, leading to the leakage of sensitive TCP sequence and acknowledgment numbers. This information disclosure could potentially be used to aid further attacks.

Red Hat severity: Moderate — CVSS 7.1 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L). Weakness: CWE-266.

Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9. Red Hat does not currently list a fixing RHSA for this CVE.

Affected products named by the advisory: Red Hat package: kernel-rt.

Is CVE-2026-53236 exploited?

No exploitation is reported in the sources VulniPulse tracks: CVE-2026-53236 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.

How do I fix CVE-2026-53236?

The advisory VulniPulse tracks names no fixed release. Follow Red Hat's guidance for workarounds and updates.

Confirm against the vendor advisory before you patch.

Affected versions

No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.

Official advisory · high-confidence parse· fetched 15 days ago·verify at source

Fixed versions

No fixed release is recorded yet. That does not prove no patch exists. Confirm against the vendor advisory.

Official advisory · high-confidence parse· fetched 15 days ago·verify at source

Mitigation checklist

Recommended fix / mitigation
  • Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Official advisory · high-confidence parse· fetched 15 days ago·verify at source

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