CVE-2026-43074

Modified Modified - Updated After Analysis

eventpoll Use-After-Free in Linux Kernel

Publication date: 2026-05-06

Last updated on: 2026-06-01

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: eventpoll: defer struct eventpoll free to RCU grace period In certain situations, ep_free() in eventpoll.c will kfree the epi->ep eventpoll struct while it still being used by another concurrent thread. Defer the kfree() to an RCU callback to prevent UAF.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-05-06

Last Modified

2026-06-01

Generated

2026-07-06

AI Q&A

2026-05-06

EPSS Evaluated

2026-07-05

NVD

CVE-2026-43074

EUVD

EUVD-2026-27558

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	6.4
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	From 6.13 (inc) to 6.18.24 (exc)
linux	linux_kernel	From 6.19 (inc) to 6.19.14 (exc)
linux	linux_kernel	From 6.7 (inc) to 6.12.83 (exc)
linux	linux_kernel	From 6.4.1 (inc) to 6.6.136 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-401	The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

Attack-Flow Graph

Executive Summary

This vulnerability exists in the Linux kernel's eventpoll subsystem. Specifically, the function ep_free() in eventpoll.c may free (kfree) the eventpoll structure (epi->ep) while it is still being accessed by another concurrent thread. This leads to a use-after-free (UAF) condition. The fix defers the freeing of this structure to an RCU (Read-Copy-Update) grace period callback, ensuring the structure is not freed while still in use.

Impact Analysis

The use-after-free vulnerability can lead to undefined behavior including potential system crashes, data corruption, or exploitation by attackers to execute arbitrary code or escalate privileges. Since the eventpoll structure may be accessed concurrently, freeing it prematurely can destabilize the kernel and compromise system security.

Mitigation Strategies

To mitigate this vulnerability, update the Linux kernel to a version where the eventpoll use-after-free issue has been fixed by deferring the kfree() call to an RCU callback.

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