VulnerabilityAnalyzed

CVE-2026-28432

All Misskey servers prior to 2026.3.1 contain a vulnerability that allows bypassing HTTP signature verification.

HIGH 7.1EPSS 0.15%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.15%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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 4.0: 7.1 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.15% probability · 4th percentile
CISA KEV: Not listed
Weakness: CWE-347
Affected: misskey/misskey
Source: security-advisories@github.com

References

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

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.