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CVE-2026-23963

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CVE-2026-23963

Published: Jan 22, 2026

Modified: Jan 22, 2026

PUBLISHED

CVSS v3.1

4.3

MEDIUM

Description

Mastodon is a free, open-source social network server based on ActivityPub. Prior to versions 4.5.5, 4.4.12, and 4.3.18, the server does not enforce a maximum length for the names of lists or filters, or for filter keywords, allowing any user to set an arbitrarily long string as the name or keyword. Any local user can abuse the list or filter fields to cause disproportionate storage and computing resource usage. They can additionally cause their own web interface to be unusable, although they must intentionally do this to themselves or unknowingly approve a malicious API client. Mastodon versions v4.5.5, v4.4.12, v4.3.18 are patched.

VendorProductVersions

mastodon

mastodon

affected
< 4.3.18
affected
>= 4.4.0, < 4.4.12
affected
>= 4.5.0, < 4.5.5

Weaknesses (CWE)

CWE-770

CVSS v3.1 Details

CVSS v3.1 Vector

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low

References

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