CVE-2024-37903

Mastodon has improper authorship check on audience extension for existing posts

HIGH
8.2
CVSS Score
Published: July 5, 2024 at 05:24 PM UTC
Updated: June 17, 2026 at 07:39 AM UTC
2 products affected across 2 vendorsMastodonMastodon

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Severity
HIGH8.2
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

Description

Mastodon is a self-hosted, federated microblogging platform. Starting in version 2.6.0 and prior to versions 4.1.18 and 4.2.10, by crafting specific activities, an attacker can extend the audience of a post they do not own to other Mastodon users on a target server, thus gaining access to the contents of a post not intended for them. Versions 4.1.18 and 4.2.10 contain a patch for this issue.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

2.6.0 ≤ v < 4.1.184.2.0 ≤ v < 4.2.102.6.04.2.0
Affected range stops below 4.1.18, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.2.10, so it looks safe — our inference, not a vendor statement
v < 4.1.18v < 4.2.10
Affected range stops below 4.1.18, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.2.10, so it looks safe — our inference, not a vendor statement

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.2HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-862

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