ZDI-26-694: Linux Kernel Net Scheduler Clsact Qdisc Use-After

Zerodayinitiative • September 14, 2026

This vulnerability allows local attackers to escalate privileges on affected installations of Linux Kernel. An attacker must first obtain the ability to execute high-privileged code on the target system in order to exploit this vulnerability.

The specific flaw exists within the handling of tcx_entry objects. The issue results from the lack of validating the existence of an object prior to performing operations on the object. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of the kernel.

Linux has issued an update to correct this vulnerability. More details can be found at:

2026-02-12 - Vulnerability reported to vendor

2026-09-14 - Coordinated public release of advisory

2026-09-14 - Advisory Updated

The full story

This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Multiple Linux Kernel Vulnerabilities Disclosed on September 14, 2026 On September 14, 2026, a series of vulnerabilities affecting the Linux Kernel were disclosed, allowing local attackers to escalate privileges or disclose sensitive information. The vulnerabilities include use-after-free issues, race conditions, and uninitialized memory access, impacting various subsystems such as Open vSwitch, TLS Protocol, and the Crypto Subsystem. Attackers must have low or high privileges to exploit these vulnerabilities, depending on the specific flaw. Linux has released updates to mitigate these vulnerabilities. The vulnerabilities were reported between December 2025 and June 2026, with the public advisories released on the same day. Affected systems include various installations of the Linux Kernel. The vulnerabilities could potentially allow attackers to execute arbitrary code in the context of the kernel. The coordinated public release of advisories indicates a significant threat to users of the affected systems. 33 sources 59

Extracted Entities

ZDI-26-694: Linux Kernel Net Scheduler Clsact Qdisc Use-After

The full story

Extracted Entities

CWE Weaknesses (1)

MITRE ATT&CK (1)

Platforms (1)

Vulnerabilities (1)