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 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 5.1th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
Threat & Defense at a Glance
Threat & Defense Details
Likely Mitigating ControlsAI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Requires verification of digital signatures using organization-approved certificates before installation, directly preventing improper verification of cryptographic signatures.
Component authenticity commonly depends on cryptographic signatures; the control enforces proper verification of those signatures.
PKI certificates under an approved policy require cryptographic signature verification on issuance and validation.
Requires cryptographic signatures on authoritative data and support for verifying the chain of trust.
Mandates verification of cryptographic signatures (e.g., DNSSEC RRSIG) on resolution responses, addressing missing or bypassed signature checks.
Integrity tools commonly rely on cryptographic signatures whose improper validation this weakness covers.
Authenticity validation commonly relies on cryptographic signature or certificate checks that this control enforces.
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.
NVD 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…
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is enabled or disabled. This vulnerability is fixed in 2026.3.1.
Deeper analysisAI
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.
Details
- CWE(s)