What’s Vulnerable › Vulnerabilities

CVE-2023-36460: Mastodon vulnerable to arbitrary file creation through media attachments

• Severity: critical (CVSS 9.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 40.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-07-06 · updated 2026-06-17
• Weakness: CWE-22

Description

Mastodon is a free, open-source social network server based on ActivityPub. Starting in version 3.5.0 and prior to versions 3.5.9, 4.0.5, and 4.1.3, attackers using carefully crafted media files can cause Mastodon's media processing code to create arbitrary files at any location. This allows attackers to create and overwrite any file Mastodon has access to, allowing Denial of Service and arbitrary Remote Code Execution. Versions 3.5.9, 4.0.5, and 4.1.3 contain a patch for this issue.

Affected products

• mastodon: from 3.5.0 before 3.5.9; from 4.0.0 before 4.0.5; from 4.1.0 before 4.1.3 — fixed in 3.5.9, 4.0.5, 4.1.3

How to fix

Upgrade to a fixed version: mastodon 3.5.9, 4.0.5, 4.1.3. Check the vendor advisory for mitigations.

References

• http://www.openwall.com/lists/oss-security/2023/07/06/4
• https://github.com/mastodon/mastodon/commit/dc8f1fbd976ae544720a4e07120d9a91b2722440
• https://github.com/mastodon/mastodon/releases/tag/v3.5.9
• https://github.com/mastodon/mastodon/releases/tag/v4.0.5
• https://github.com/mastodon/mastodon/releases/tag/v4.1.3
• https://github.com/mastodon/mastodon/security/advisories/GHSA-9928-3cp5-93fm
• http://www.openwall.com/lists/oss-security/2023/07/06/4
• https://github.com/mastodon/mastodon/commit/dc8f1fbd976ae544720a4e07120d9a91b2722440
• https://github.com/mastodon/mastodon/releases/tag/v3.5.9
• https://github.com/mastodon/mastodon/releases/tag/v4.0.5
• https://github.com/mastodon/mastodon/releases/tag/v4.1.3
• https://github.com/mastodon/mastodon/security/advisories/GHSA-9928-3cp5-93fm

Get alerted when CVE-2023-36460 or the next vulnerability affects your stack