CVE-2026-33869

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.

CVSS v3 4.8 MEDIUM

4.8^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.2 / Impact : 2.5

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact LOW

Scope UNCHANGED

References

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

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:joinmastodon:mastodon::::::::
	cpe:2.3:a:joinmastodon:mastodon::::::::

History

No history.

Information

Published : 2026-03-27 20:16

Updated : 2026-06-17 10:38

NVD link : CVE-2026-33869

Mitre link : CVE-2026-33869

CVE.ORG link : CVE-2026-33869

JSON object : View

Products Affected

joinmastodon

mastodon

CWE

CWE-863

Incorrect Authorization

{"id": "CVE-2026-33869", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-33869", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-03-27T20:29:10.346345Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 4.8, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "LOW", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 2.5, "exploitabilityScore": 2.2}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "mastodon", "product": "mastodon", "versions": [{"status": "affected", "version": ">= 4.5.0, < 4.5.8"}, {"status": "affected", "version": ">= 4.4.0, < 4.4.15"}]}]}], "published": "2026-03-27T20:16:34.500", "references": [{"url": "https://github.com/mastodon/mastodon/security/advisories/GHSA-q4g8-82c5-9h33", "tags": ["Vendor Advisory"], "source": "security-advisories@github.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-863"}]}], "descriptions": [{"lang": "en", "value": "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."}], "lastModified": "2026-06-17T10:38:14.000", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "A37B2AD4-5027-464B-947A-63BDB06C33B8", "versionEndExcluding": "4.4.15", "versionStartIncluding": "4.4.0"}, {"criteria": "cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "BE32DA85-D71D-4CB8-8216-205780DBBB6A", "versionEndExcluding": "4.5.8", "versionStartIncluding": "4.5.0"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}