Improper Verification of Cryptographic Signature in Misskey - CVE-2026-28432
Published: April 28, 2026
Vulnerability identifier: #VU128341
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-28432
CWE-ID: CWE-347
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Misskey Development Division
Affected software:
Misskey
Misskey
Detailed vulnerability description
The vulnerability allows a remote attacker to bypass HTTP signature verification.
The vulnerability exists due to improper verification of cryptographic signature in HTTP signature verification when handling federation-related HTTP signatures. A remote attacker can send a specially crafted signed request to bypass HTTP signature verification.
The issue affects all servers regardless of whether federation is enabled or disabled.
How to mitigate CVE-2026-28432
Install security update from vendor's website.