CVE-2026-28432

HTTP signature verification can be bypassed

HIGH
7.5
CVSS Score
Published: March 9, 2026 at 09:19 PM UTC
Updated: June 17, 2026 at 10:28 AM UTC
2 products affected across 2 vendorsMisskeyMisskey

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Severity
HIGH7.5
Exploit prediction
EPSS 0.2%
SSVC
No known 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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 2026.3.1
v < 2026.3.1
Affected range stops below 2026.3.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-347

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