CVE-2026-28432 PUBLISHED

HTTP signature verification can be bypassed

Assigner: GitHub_M
Reserved: 27.02.2026 Published: 09.03.2026 Updated: 09.03.2026

Misskey is an open source, federated social media platform. All Misskey servers prior to 2026.3.1 contain a vulnerability that allows bypassing HTTP signature verification. Although this is a vulnerability related to federation, it affects all servers regardless of whether federation is enabled or disabled. This vulnerability is fixed in 2026.3.1.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N
CVSS Score: 7.1

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	Low	Confidentiality	None
Attack Complexity	Low	Integrity	High	Integrity	None
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	None
User Interaction	Passive

CVSS 4.0

Product Status

Vendor	misskey-dev
Product	misskey
Versions	Version < 2026.3.1 is affected

References

https://github.com/misskey-dev/misskey/security/advisories/GHSA-grwc-c762-gcvp

Problem Types

CWE-347: Improper Verification of Cryptographic Signature CWE