CVE-2026-46349
CVE-2026-46349 is a medium-severity vulnerability with a CVSS 3.x base score of 5.3. 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: Medium (CVSS 3.x base score 5.3)
- EPSS exploit prediction: 0% (6th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-39054
- Weakness: CWE-347
- Published:
- Last modified:
Description
Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.23, Mastodon's normalization of incoming activities signed with Linked-Data Signatures does not sufficiently protect the activities from a certain class of spoofing, allowing attackers to re-arrange a valid signed JSON-LD activity from a third-party actor to have it processed differently. This vulnerability is fixed in 4.5.10, 4.4.17, and 4.3.23.
Frequently asked questions
- What is CVE-2026-46349?
- Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.23, Mastodon's normalization of incoming activities signed with Linked-Data Signatures does not sufficiently protect the activities from a certain class of spoofing, allowing attackers to re-arrange a valid signed JSON-LD activity from a third-party actor to have it processed differently. This vulnerability is fixed in 4.5.10, 4.4.17, and 4.3.23.
- How severe is CVE-2026-46349?
- CVE-2026-46349 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
- Is CVE-2026-46349 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-46349?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2026-46349 have an EU (EUVD) identifier?
- Yes. CVE-2026-46349 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-39054.
- When was CVE-2026-46349 published?
- CVE-2026-46349 was published on 2026-06-24 and last updated on 2026-06-25.
References
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 →