CVE-2026-23962: high-severity vulnerability in mastodon
Mastodon vulnerable to Denial of Service from a single post (client/server)
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.5epss 0.5%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
mastodon · mastodonRelated CVEs — mastodon
In the same product, most dangerous first.
CVE-2023-36460CRITICALMastodon vulnerable to arbitrary file creation through media attachmentsEPSS 40.1%CVE-2024-23832CRITICALMastodon Remote user impersonation and takeoverEPSS 2.5%CVE-2023-36461HIGHMastodon vulnerable to Denial of Service through slow HTTP responsesEPSS 1.3%CVE-2023-28853HIGHMastodon's blind LDAP injection in login allows the attacker to leak arbitrary attributes from LDAP databaseEPSS 1.3%CVE-2023-36459CRITICALMastodon vulnerable to Cross-site Scripting through oEmbed preview cardsEPSS 1.2%CVE-2026-72916MEDIUMMastodon: SSRF Protection Bypass via IPv4-compatible IPv6 AddressesEPSS 1.0%