TI-2025-41257 Aliases CVE-2025-67500

Mastodon Error Handling Discrepancy Enables Private Status Existence Enumeration

LOW 17CWE-204Published 2025-12-09 · Updated 2026-01-08

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: High
Impact type: Information disclosure
Confidentiality · integrity · availability: Low · None · None
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-204.

Summary

Mastodon 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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00224 13th percentileScored 2026-11-07

Fix Fixed mastodon (mastodon): 4.2.28, 4.3.15, 4.4.10 +1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
mastodon	mastodon	before 4.2.28; 4.3.0-beta.1 to before 4.3.15; 4.4.0-beta.1 to before 4.4.10; 4.5.0-beta.1 to before 4.5.3	4.2.28, 4.3.15, 4.4.10, 4.5.3	Patch available	CNA

mastodon Vendormastodon Affected before 4.2.28; 4.3.0-beta.1 to before 4.3.15; 4.4.0-beta.1 to before 4.4.10; 4.5.0-beta.1 to before 4.5.3 Fixed in 4.2.28, 4.3.15, 4.4.10, 4.5.3 Patch available CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:joinmastodon:mastodon::::::::	before 4.2.28; 4.3.0 to before 4.3.15; 4.4.0 to before 4.4.10; 4.5.0 to before 4.5.3	Vulnerable	mastodon

cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:* Versions before 4.2.28; 4.3.0 to before 4.3.15; 4.4.0 to before 4.4.10; 4.5.0 to before 4.5.3 Vulnerable ·mastodon

Remediation

Fix · CNA mastodon (mastodon) Fixed in 4.2.28, 4.3.15, 4.4.10, 4.5.3

Timeline

2026-10-02 Threatist record created from CVE-2025-67500

References

Patch 1

https://github.com/mastodon/mastodon/pull/37077/commits/9957d3218cb33fea6a44bb285e2ba4795a059e4f

Advisory 1

https://github.com/mastodon/mastodon/security/advisories/GHSA-gwhw-gcjx-72v8

TI-2022-02004 Improper Restriction of Excessive Authentication Attempts in mastodon/mastodon CVSS 3.1CRITICAL 9.8
TI-2025-34613 Mastodon e‑mail throttle misconfiguration allows unlimited email confirmations against unconfirmed emails CVSS 3.1HIGH 7.5
TI-2022-22936 Mastodon through 4.0.2 allows attackers to cause a denial of service (large Sidekiq pull… CVSS 3.1HIGH 7.5
TI-2023-18301 Mastodon vulnerable to arbitrary file creation through media attachments CVSS 3.1CRITICAL 10.0
TI-2023-13359 Mastodon's blind LDAP injection in login allows the attacker to leak arbitrary attributes from LDAP database CVSS 3.1HIGH 7.7
TI-2024-16846 External OpenID Connect Account Takeover by E-Mail Change in mastodon CVSS 3.1HIGH 7.4

See all 41 →

Sources

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