High severity · published Mar 9, 2026
CVE-2026-28432
HTTP signature verification can be bypassed
7.5
CVSS
0.2%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 5% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MI
misskey · misskey-dev
< 2026.3.1 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-28432
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-28432
Vendor Advisory
https://github.com/misskey-dev/misskey/security/advisories/GHSA-grwc-c762-gcvp
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