How serious is CVE-2025-21836?

This vulnerability has a CVSS score of 5.5 out of 10, classified as MEDIUM severity. Proof-of-concept exploit code is publicly available, making this an active threat.

Is there exploit code available for CVE-2025-21836?

Yes, proof-of-concept exploit code for CVE-2025-21836 is publicly available on GitHub and security research platforms. This increases the risk of active exploitation.

Which products are affected by CVE-2025-21836?

CVE-2025-21836 affects linux linux kernel. Check the full CVE details for specific version information.

How do I fix CVE-2025-21836?

To remediate CVE-2025-21836, check for security patches from linux. Apply all available updates and security patches. If no patch is available, implement recommended workarounds or security controls to mitigate the risk.

CVE-2025-21836

Medium

|5.5

Exploit Available

Plain English Summary

AI-powered analysis for quick understanding

This vulnerability allows an attacker to potentially manipulate memory in the Linux kernel, which could lead to unexpected behavior or crashes in applications using the io_uring interface. It occurs when an old buffer structure is reused improperly after being emptied, which could happen under specific conditions when upgrading buffer settings.

Technical Description

In the Linux kernel, the following vulnerability has been resolved: io_uring/kbuf: reallocate buf lists on upgrade IORING_REGISTER_PBUF_RING can reuse an old struct io_buffer_list if it was created for legacy selected buffer and has been emptied. It violates the requirement that most of the field should stay stable after publish. Always reallocate it instead.

CVSS Vector Analysis

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

Confidentiality ImpactNone

Integrity ImpactNone

Availability ImpactHigh

ScopeUnchanged

Vector String

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Exploit Resources

Search for proof-of-concept code and exploit modules

GitHub Search Exploit-DB Nuclei Templates Metasploit Vulners

Official References

NIST NVD

Est. Bounty

$759($500-$1K)

Vendor Response

Grade FPatched in 365 days

Quick Information

Published

Mar 7, 2025

about 1 year ago

Last Modified

Mar 7, 2026

about 1 month ago

Vendor

linux

Product

linux kernel

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