CVE-2026-47777

HIGHPre-NVD 7.57.5—

7.5

EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.

High severity, but no confirmed exploitation yet

CISA-KEV: Not listedEPSS: 0%CVSS: 7.5Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Mastodon is a free, open-source social network server based on ActivityPub. In versions there is a missing condition in the check if remote accounts consented to be featured in a remote Collection could lead to attackers bypassing the check and faking consent. An attacker could forge the FeatureAuthorization object that is used to verify consent to be featured in a Collection and thus make it appear as if an account is allowed to be in a Collection when it actually is not. While the FeatureAuthorization must reside on the same domain as the object it is for, a check is missing to make sure said object is actually the same as in the Collection item. This allows an attacker to forge the authorization. Mastodon servers are affected only if running the main branch or nightly builds who have opted into testing the experimental "Collections" feature by setting the environment variable EXPERIMENTAL_FEATURES to a value including collections. This has been patched in version 4.6.0-beta.1.

CVSS v3: 7.5
EG Score: 7.5(medium)
EPSS: 6.3%
KEV: Not listed

Published

June 15, 2026

Last Modified

June 16, 2026

Advisory Details (2)

Auto-updated Jun 15, 2026

Patch available. Sources: github, github_commit.

github_commit Patch Available

commit 22203f8aeb03 (mastodon/mastodon)

Patch available: mastodon/mastodon v4.6.0-beta.1 (contains commit 22203f8aeb03)

https://github.com/mastodon/mastodon/commit/22203f8aeb03e8f14dc62e253e83db39825a5bcf

github Patch Available

Consent-check bypass in remote Collections · Advisory · mastodon/mastodon · GitHub

https://github.com/mastodon/mastodon/security/advisories/GHSA-vg36-gxjg-2v46

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Frequently asked(5)

What is CVE-2026-47777?

CVE-2026-47777 is a high vulnerability published on June 15, 2026. Mastodon is a free, open-source social network server based on ActivityPub. In versions there is a missing condition in the check if remote accounts consented to be featured in a remote Collection could lead to attackers bypassing the check and faking consent. An attacker could forge the…

When was CVE-2026-47777 disclosed?

CVE-2026-47777 was first published in the National Vulnerability Database on June 15, 2026, with the most recent update on June 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2026-47777 actively exploited?

CVE-2026-47777 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 6.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2026-47777?

CVE-2026-47777 has a CVSS v3 base score of 7.5 (NVD).

How do I remediate CVE-2026-47777?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-47777, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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