How severe is CVE-2026-28432?

CVE-2026-28432 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2026-28432 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-28432?

CVE-2026-28432 affects Misskey. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-28432?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-28432 have an EU (EUVD) identifier?

Yes. CVE-2026-28432 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-10367.

When was CVE-2026-28432 published?

CVE-2026-28432 was published on 2026-03-10 and last updated on 2026-06-17.

CVE-2026-28432

CVE-2026-28432 is a high-severity vulnerability in Misskey with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-347.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 7.1
EPSS exploit prediction: 0% (4th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-10367
Weakness: CWE-347
Affected product: Misskey
Published: 2026-03-10
Last modified: 2026-06-17

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.

Frequently asked questions

What is 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.
How severe is CVE-2026-28432?: CVE-2026-28432 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2026-28432 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-28432?: CVE-2026-28432 affects Misskey. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-28432?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-28432 have an EU (EUVD) identifier?: Yes. CVE-2026-28432 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-10367.
When was CVE-2026-28432 published?: CVE-2026-28432 was published on 2026-03-10 and last updated on 2026-06-17.

References

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

Affected products (1)

cpe:2.3:a:misskey:misskey:*:*:*:*:*:*:*:*

More vulnerabilities in Misskey

CVE-2025-25306 — Critical (CVSS 9.3): Misskey is an open source, federated social media platform. The patch for CVE-2024-52591 did not sufficiently validate…
CVE-2024-52591 — Critical (CVSS 9.3): Misskey is an open source, federated social media platform. In affected versions missing validation in…
CVE-2023-49079 — Critical (CVSS 9.3): Misskey is an open source, decentralized social media platform. Misskey's missing signature validation allows arbitrary…
CVE-2023-52139 — Critical (CVSS 9.0): Misskey is an open source, decentralized social media platform. Third-party applications may be able to access some…
CVE-2023-24812 — High (CVSS 8.8): Misskey is an open source, decentralized social media platform. In versions prior to 13.3.3 SQL injection is possible…
CVE-2025-24897 — High (CVSS 8.2): Misskey is an open source, federated social media platform. Starting in version 12.109.0 and prior to version…

All CVEs affecting Misskey →

Other CWE-347 (Improper Verification of Cryptographic Signature) vulnerabilities

CVE-2026-48558 — Critical (CVSS 10.0): SimpleHelp versions 5.5.15 and prior and 6.0 pre-release versions contain an authentication bypass vulnerability in the…
CVE-2023-25574 — Critical (CVSS 10.0): `jupyterhub-ltiauthenticator` is a JupyterHub authenticator for learning tools interoperability (LTI).…
CVE-2024-45409 — Critical (CVSS 10.0): The Ruby SAML library is for implementing the client side of a SAML authorization. Ruby-SAML in <= 12.2 and 1.13.0 <=…
CVE-2024-32962 — Critical (CVSS 10.0): xml-crypto is an xml digital signature and encryption library for Node.js. In affected versions the default…
CVE-2022-24884 — Critical (CVSS 10.0): ecdsautils is a tiny collection of programs used for ECDSA (keygen, sign, verify). `ecdsa_verify_[prepare_]legacy()`…
CVE-2021-33885 — Critical (CVSS 10.0): An Insufficient Verification of Data Authenticity vulnerability in B. Braun SpaceCom2 prior to 012U000062 allows a…

Browse all CWE-347 (Improper Verification of Cryptographic Signature) vulnerabilities →