Description

Mastodon is a free, open-source social network server based on ActivityPub. Mastodon allows new identities from configured authentication providers (CAS, SAML, OIDC) to attach to existing local users with the same e-mail address. This results in a possible account takeover if the authentication provider allows changing the e-mail address or multiple authentication providers are configured. When a user logs in through an external authentication provider for the first time, Mastodon checks the e-mail address passed by the provider to find an existing account. However, using the e-mail address alone means that if the authentication provider allows changing the e-mail address of an account, the Mastodon account can immediately be hijacked. All users logging in through external authentication providers are affected. The severity is medium, as it also requires the external authentication provider to misbehave. However, some well-known OIDC providers (like Microsoft Azure) make it very easy to accidentally allow unverified e-mail changes. Moreover, OpenID Connect also allows dynamic client registration. This issue has been addressed in versions 4.2.6, 4.1.14, 4.0.14, and 3.5.18. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Severity

 

CVSS Version 3.x CVSS Version 2.0

CVSS 3.x Severity and Metrics:

NIST: NVD

Base Score:  N/A

NVD assessment not yet provided.

CNA:  GitHub, Inc.

Base Score:  4.2 MEDIUM

Vector:  CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N

NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have not published a CVSS score for this CVE at this time. NVD Analysts use publicly available information at the time of analysis to associate CVSS vector strings. A CNA provided score within the CVE List has been displayed.

CVSS 2.0 Severity and Metrics:

NIST: NVD

Base Score: N/A

NVD assessment not yet provided.

NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have not published a CVSS score for this CVE at this time. NVD Analysts use publicly available information at the time of analysis to associate CVSS vector strings.

References to Advisories, Solutions, and Tools

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Hyperlink	Resource
https://github.com/mastodon/mastodon/commit/b31af34c9716338e4a32a62cc812d1ca59e88d15
https://github.com/mastodon/mastodon/security/advisories/GHSA-vm39-j3vx-pch3

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-287	Improper Authentication	GitHub, Inc.

Change History

1 change records found show changes

New CVE Received by NIST 2/14/2024 4:15:08 PM

Action	Type	Old Value	New Value
Added	CVSS V3.1		GitHub, Inc. AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
Added	CWE		GitHub, Inc. CWE-287
Added	Description		Record truncated, showing 500 of 1275 characters. View Entire Change Record Mastodon is a free, open-source social network server based on ActivityPub. Mastodon allows new identities from configured authentication providers (CAS, SAML, OIDC) to attach to existing local users with the same e-mail address. This results in a possible account takeover if the authentication provider allows changing the e-mail address or multiple authentication providers are configured. When a user logs in through an external authentication provider for the first time, Mastodon checks the e-m
Added	Reference		GitHub, Inc. https://github.com/mastodon/mastodon/commit/b31af34c9716338e4a32a62cc812d1ca59e88d15 [No types assigned]
Added	Reference		GitHub, Inc. https://github.com/mastodon/mastodon/security/advisories/GHSA-vm39-j3vx-pch3 [No types assigned]