What is CVE-2026-28432?

CVE-2026-28432 is a high-severity vulnerability in Misskey, classified under Improper Verification of Cryptographic Signature. CVSS score: 7.5/10. Published 2026-03-10.

How severe is CVE-2026-28432?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Misskey

CVE-2026-28432

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.

Published 2026-03-10 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.002 (13.7th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 14th percentile — 13.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · change: +0.001

Affected products

Misskey
Misskey-Dev Misskey — versions < 2026.3.1

Weakness classification (CWE)

CWE-347 — Improper Verification of Cryptographic Signature

References

github.com/misskey-dev/misskey/security/advisories/GHSA-grwc-c762-gcvp (Vendor Advisory)

Frequently asked questions

What is CVE-2026-28432?: CVE-2026-28432 is a high-severity vulnerability in Misskey, classified under Improper Verification of Cryptographic Signature. CVSS score: 7.5/10. Published 2026-03-10.
How severe is CVE-2026-28432?: High severity. CVSS v3 base score is 7.5 out of 10.