How serious is CVE-2026-28431?

This vulnerability has a CVSS score of 9.2 out of 10, classified as CRITICAL severity. Proof-of-concept exploit code is publicly available, making this an active threat.

Is there exploit code available for CVE-2026-28431?

Yes, proof-of-concept exploit code for CVE-2026-28431 is publicly available on GitHub and security research platforms. This increases the risk of active exploitation.

Which products are affected by CVE-2026-28431?

CVE-2026-28431 affects misskey misskey. Check the full CVE details for specific version information.

How do I fix CVE-2026-28431?

To remediate CVE-2026-28431, check for security patches from misskey. Apply all available updates and security patches. If no patch is available, implement recommended workarounds or security controls to mitigate the risk.

CVE-2026-28431

Critical

|9.2

Exploit Available

Plain English Summary

AI-powered analysis for quick understanding

This vulnerability allows attackers to access sensitive data on Misskey servers that they shouldn't be able to see, potentially leading to a major data breach. It affects all versions from 8.45.0 up to, but not including, 2026.3.1, regardless of whether the server's federation feature is turned on.

Technical Description

Misskey is an open source, federated social media platform. All Misskey servers running versions 8.45.0 and later, but prior to 2026.3.1, contain a vulnerability that allows bad actors access to data that they ordinarily wouldn't be able to access due to insufficient permission checks and proper input validation. This vulnerability occurs regardless of whether federation is enabled or not. This vulnerability could lead to a significant data breach. This vulnerability is fixed in 2026.3.1.

CVSS Vector Analysis

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

Confidentiality ImpactHigh

Integrity ImpactHigh

Availability ImpactHigh

ScopeChanged

Vector String

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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

$7,000($5K-$15K)

Vendor Response

Grade APatched in 3 days

Quick Information

Published

Mar 10, 2026

28 days ago

Last Modified

Mar 13, 2026

25 days ago

Vendor

misskey

Product

misskey

Related Vulnerabilities

CVE-2026-28433Low

This vulnerability allows an attacker to import other users' data from Misskey servers, but they need to know the specific ID of the file they want to access. While the risk is considered low, it still poses a potential privacy issue for users on affected versions of the platform.

CVE-2026-28432High

An attacker can bypass security checks that verify the authenticity of messages sent between Misskey servers, which could allow them to send fake or malicious content. This vulnerability affects all Misskey servers, regardless of whether they are set up to communicate with other servers or not, and it has been fixed in the latest version.