Mastodon Error Handling Discrepancy Enables Private Status Existence Enumeration

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-67500
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-12-10 00:16:11 UTC
Updated2026-10-14 21:10:00 UTC
DescriptionMastodon is a free, open-source social network server based on ActivityPub. Versions 4.2.27 and prior, 4.3.0-beta.1 through 4.3.14, 4.4.0-beta.1 through 4.4.9, 4.5.0-beta.1 through 4.5.2 have discrepancies in error handling which allow checking whether a given status exists by sending a request with a non-English Accept-Language header. Using this behavior, an attacker who knows the identifier of a particular status they are not allowed to see can confirm whether this status exists or not. This cannot be used to learn the contents of the status or any other property besides its existence. This issue is fixed in versions 4.2.28, 4.3.15, 4.4.10 and 4.5.3.

Risk And Classification

Primary CVSS: v3.1 3.7 LOW from [email protected]

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

Problem Types: CWE-204 | CWE-204 CWE-204: Observable Response Discrepancy

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary3.7LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
3.1[email protected]Secondary3.7LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
3.1CNADECLARED3.7LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Joinmastodon Mastodon All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Mastodon Mastodon affected < 4.2.28 Not specified
CNA Mastodon Mastodon affected >= 4.3.0-beta.1, < 4.3.15 Not specified
CNA Mastodon Mastodon affected >= 4.4.0-beta.1, < 4.4.10 Not specified
CNA Mastodon Mastodon affected >= 4.5.0-beta.1, < 4.5.3 Not specified

References

ReferenceSourceLinkTags
github.com/mastodon/mastodon/security/advisories/GHSA-gwhw-gcjx-72v8 [email protected] github.com Vendor Advisory
github.com/mastodon/mastodon/pull/37077/commits/9957d3218cb33fea6a44bb28... [email protected] github.com Patch
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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