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Advisory severityHigh7.0Vendor: MediumRed Hat Linux

High [CVE-2026-53075] require CAP_NET_ADMIN in target netns for unattached ioctls

This high-severity Red Hat Linux advisory covers CVE-2026-53075 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 7.

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

CVE-2026-53075 Source published Source updated

VulniPulse record published Record updated

CVE-2026-53075
Affected products & platforms
Red Hat LinuxLinux Kernel
Open source advisory

Summary

In the Linux kernel, the following vulnerability has been resolved: ppp: require CAP_NET_ADMIN in target netns for unattached ioctls /dev/ppp open is currently authorized against file->f_cred->user_ns, while unattached administrative ioctls operate on current->nsproxy->net_ns.

As a result, a local unprivileged user can create a new user namespace with CLONE_NEWUSER, gain CAP_NET_ADMIN only in that new user namespace, and still issue PPPIOCNEWUNIT, PPPIOCATTACH, or PPPIOCATTCHAN against an inherited network namespace.

Require CAP_NET_ADMIN in the user namespace that owns the target network namespace before handling unattached PPP administrative ioctls. This preserves normal pppd operation in the network namespace it is actually privileged in, while rejecting the userns-only inherited-netns case.

A flaw was found in the Linux kernel's Point-to-Point Protocol (PPP) subsystem. A local unprivileged user can exploit this vulnerability by creating a new user namespace and bypassing authorization checks for unattached administrative input/output controls (ioctls).

This allows the user to perform unauthorized administrative operations on an inherited network namespace, potentially leading to privilege escalation. Red Hat severity: Moderate — CVSS 7 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H).

Weakness: CWE-266.

Is CVE-2026-53075 exploited?

No exploitation is reported in the sources VulniPulse tracks: CVE-2026-53075 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-2026-53075?

Upgrade to a fixed release named by Red Hat:

  • kernel-0:6.12.0-211.52.1.el10_2
  • kernel-rt-0:4.18.0-553.164.1.rt7.505.el8_10
  • kernel-0:4.18.0-553.164.1.el8_10
  • RHSA-2026:64775
  • RHSA-2026:68532
  • RHSA-2026:68531

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 14 days ago·verify at source

Fixed versions
  • kernel-0:6.12.0-211.52.1.el10_2
  • kernel-rt-0:4.18.0-553.164.1.rt7.505.el8_10
  • kernel-0:4.18.0-553.164.1.el8_10
  • RHSA-2026:64775
  • RHSA-2026:68532
  • RHSA-2026:68531

Official advisory · high-confidence parse· fetched 14 days ago·verify at source

Mitigation

Upgrade to a fixed release: kernel-0:6.12.0-211.52.1.el10_2, kernel-rt-0:4.18.0-553.164.1.rt7.505.el8_10, kernel-0:4.18.0-553.164.1.el8_10, RHSA-2026:64775, RHSA-2026:68532, RHSA-2026:68531. That is the remediation for this advisory.

The vendor advisory may list interim mitigations or workarounds not captured here. Review it before change work.

Official advisory · high-confidence parse· fetched 14 days ago·verify at source

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