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CVE-2026-33869

Mastodon has a denial of service for quote authorization

Published: Mar 27, 2026Updated: Mar 30, 2026 Sources: CVE List NVDCWE-863
4.8MEDIUM
NVD MITRE
EPSS Score
0.2%
Top 93.9%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

Mastodon is a free, open-source social network server based on ActivityPub. In versions on the 4.5.x branch prior to 4.5.8 and on the 4.4.x branch prior to 4.4.15, an attacker that knows of a quote before it has reached a server can prevent it from being correctly processed on that server. The vulnerability has been patched in Mastodon 4.5.8 and 4.4.15. Mastodon 4.3 and earlier are not affected because they do not support quotes.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:HPR:NUI:NS:UC:NI:LA:L
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:LIntegrity
Low
A:LAvailability
Low
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Weaknesses

CWE-863

Affected Products

mastodonmastodon
On-prem
Communications / messaging-chat
mastodonjoinmastodon
On-prem
Communications / messaging-chat
mastodonoss-projectCommunicationsaka mastodon/mastodon
joinmastodonoss-projectCommunicationsaka mastodon

Exploitability

Official Patch Available

Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques
Initial Access
View detailed technique mapping

References

https://github.com/mastodon/mastodon/security/advisories/GHSA-q4g8-82c5-9h33
github.com

Timeline

Published
Mar 27, 2026
Last Updated
Mar 30, 2026

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