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Privilege escalation vulnerability in Linux kernel’s Eventpoll subsystem (Bad Epoll)

Indian – Computer Emergency Response Team (https://www.cert-in.org.in)

Severity Rating: HIGH

Software Affected

Linux Kernel versions 5.15.209 to 5.15.x

Linux Kernel versions 6.1.175 to 6.1.x

Linux Kernel versions 6.4 to 6.18.32

Linux Kernel versions 6.19 to 7.0.9

Overview

A vulnerability commonly referred to as ‘Bad Epoll’ has been reported in the Linux Kernel’s Eventpoll (epoll) subsystem that could allow a local authenticated attacker to escalate privileges on the targeted system.

Target Audience:

All organizations and individuals running affected versions of Linux Kernel.

Risk Assessment:

High risk of local privilege escalation, race condition, execute arbitrary code and memory corruption.

Impact Assessment:

Potential for privilege escalation, execute arbitrary code with kernel privileges, memory corruption, system compromise and disruption of affected systems.

Description

The Linux kernel is the core component of many operating systems, responsible for managing hardware resources and providing essential system services and memory management functionality.

The vulnerability exists in the Linux kernel Eventpoll (epoll) subsystem due to a use-after-free (UAF) condition in the ep_remove() function. An authenticated local attacker could exploit this race condition by triggering concurrent operations on affected kernel objects, causing memory corruption and obtaining elevated privileges.

Successful exploitation of this vulnerability could allow an authenticated local attacker to gain elevated privileges, potentially resulting in the complete compromise of the affected system.

Solution

Apply appropriate updates as mentioned by the vendor:

https://www.kernel.org/

Vendor Information

Linux Kernel

https://www.kernel.org/

References

 

https://www.kernel.org/

CVE Name

CVE-2026-46242

 

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Thanks and Regards,

CERT-In

Incident Response Help Desk

e-mail: incident@cert-in.org.in

Phone: +91-11-22902657

Toll Free Number: 1800-11-4949

Toll Free Fax : 1800-11-6969

Web: http://www.cert-in.org.in

PGP Fingerprint: A768 083E 4475 5725 B81A A379 2156 C0C0 B620 D0B4

PGP Key information:

https://www.cert-in.org.in/s2cMainServlet?pageid=CONTACTUS

Postal address:

Indian Computer Emergency Response Team (CERT-In)

Ministry of Electronics and Information Technology

Government of India

Electronics Niketan

6, C.G.O. Complex

New Delhi-110 003

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