CVE-2026-28432
Published: 10 March 2026
Summary
CVE-2026-28432 is a high-severity Improper Verification of Cryptographic Signature (CWE-347) vulnerability in Misskey Misskey. Its CVSS base score is 7.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 5.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 RA-5 (Vulnerability Monitoring and Scanning) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2026-28432 is a vulnerability in Misskey, an open-source federated social media platform, that allows bypassing HTTP signature verification. It affects all Misskey servers running versions prior to 2026.3.1, regardless of whether federation is enabled or disabled. The issue, published on 2026-03-10, is classified under CWE-347 (Improper Verification of Cryptographic Signature) with a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N), indicating high integrity impact without affecting confidentiality or availability.
Remote attackers can exploit this vulnerability over the network with low attack complexity, no required privileges, and no user interaction. Exploitation enables bypassing HTTP signature verification, primarily in federation-related communications, allowing attackers to forge or manipulate requests that would otherwise be rejected due to invalid signatures.
The vulnerability is addressed in Misskey version 2026.3.1. Administrators should upgrade to this patched release. Additional details are available in the GitHub security advisory at https://github.com/misskey-dev/misskey/security/advisories/GHSA-grwc-c762-gcvp.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-10367
Vulnerability details
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…
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is enabled or disabled. This vulnerability is fixed in 2026.3.1.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Bypass of HTTP signature verification in public Misskey server directly enables remote exploitation of a public-facing application without credentials or interaction.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly mitigates CVE-2026-28432 by requiring timely identification, reporting, and correction of the HTTP signature verification flaw through patching to Misskey version 2026.3.1.
Enables proactive detection of the improper cryptographic signature verification vulnerability in vulnerable Misskey versions via regular automated vulnerability scanning.
Ensures receipt and implementation of security advisories, such as the GitHub advisory for CVE-2026-28432, facilitating rapid awareness and patching of the signature bypass issue.