Mastodon up to 4.3.17/4.4.11/4.5.4 Poll Option allocation of resources

Summaryinfo

A vulnerability labeled as problematic has been found in Mastodon up to 4.3.17/4.4.11/4.5.4. This vulnerability affects unknown code of the component Poll Option Handler. Executing a manipulation can lead to allocation of resources. This vulnerability appears as CVE-2026-23962. The attack may be performed from remote. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Mastodon up to 4.3.17/4.4.11/4.5.4. It has been declared as problematic. This vulnerability affects an unknown part of the component Poll Option Handler. The manipulation with an unknown input leads to a allocation of resources vulnerability. The CWE definition for the vulnerability is CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. As an impact it is known to affect availability. CVE summarizes:

Mastodon is a free, open-source social network server based on ActivityPub. Mastodon versions before v4.3.18, v4.4.12, and v4.5.5 do not have a limit on the maximum number of poll options for remote posts, allowing attackers to create polls with a very large amount of options, greatly increasing resource consumption. Depending on the number of poll options, an attacker can cause disproportionate resource usage in both Mastodon servers and clients, potentially causing Denial of Service either server-side or client-side. Mastodon versions v4.5.5, v4.4.12, v4.3.18 are patched.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-23962 since 01/19/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 4.3.18, 4.4.12 or 4.5.5 eliminates this vulnerability. The upgrade is hosted for download at github.com.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-4208). Once again VulDB remains the best source for vulnerability data.

Productinfo

Name

• Mastodon

Version

• 4.3.0
• 4.3.1
• 4.3.2
• 4.3.3
• 4.3.4
• 4.3.5
• 4.3.6
• 4.3.7
• 4.3.8
• 4.3.9
• 4.3.10
• 4.3.11
• 4.3.12
• 4.3.13
• 4.3.14
• 4.3.15
• 4.3.16
• 4.3.17
• 4.4.0
• 4.4.1
• 4.4.2
• 4.4.3
• 4.4.4
• 4.4.5
• 4.4.6
• 4.4.7
• 4.4.8
• 4.4.9
• 4.4.10
• 4.4.11
• 4.5.0
• 4.5.1
• 4.5.2
• 4.5.3
• 4.5.4

Website

• Product: https://github.com/mastodon/mastodon/

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Once again VulDB remains the best source for vulnerability data.

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