What is the CVSS score of CVE-2026-25808?

CVE-2026-25808 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. EPSS exploitation probability: 0.0%.

Which versions of Fedify are affected by CVE-2026-25808?

Hollo microblogging instances running versions prior to 0.6.20 and 0.7.2 expose private direct messages and followers-only posts to unauthorized users through a publicly accessible endpoint.. A patch is available.

Is there a public PoC exploit available for CVE-2026-25808?

Yes, a public proof-of-concept exploit is available for CVE-2026-25808. Prioritise patching immediately. EPSS: 0.0%.

How to fix or mitigate CVE-2026-25808?

Within 24 hours: Identify all Hollo instances in your environment and verify current versions. Within 7 days: Apply vendor patches to upgrade to version 0.6.20 or 0.7.2 (or later). Within 30 days: Conduct audit logs to determine if private content was accessed via the ActivityPub outbox endpoint during the vulnerable period; notify affected users if unauthorized access is confirmed.

Fedify CVE-2026-25808

HIGH

Missing Authorization (CWE-862)

2026-02-09 security-advisories@github.com

Authentication Bypass Fedify Hollo

7.5

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

7.5 HIGH

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 21:54 vuln.today

PoC Detected

Feb 28, 2026 - 00:17 vuln.today

Public exploit code

Patch released

Feb 28, 2026 - 00:17 nvd

Patch available

CVE Published

Feb 09, 2026 - 22:16 nvd

HIGH 7.5

DescriptionGitHub Advisory

Hollo is a federated single-user microblogging software designed to be federated through ActivityPub. Prior to 0.6.20 and 0.7.2, there is a security vulnerability where DMs and followers-only posts were exposed through the ActivityPub outbox endpoint without authorization. This vulnerability is fixed in 0.6.20 and 0.7.2.

AnalysisAI

Hollo versions prior to 0.6.20 and 0.7.2 improperly expose direct messages and followers-only posts through the ActivityPub outbox endpoint, allowing unauthenticated remote attackers to access sensitive user communications. Public exploit code exists for this authorization bypass vulnerability, enabling attackers to enumerate and retrieve private content intended for restricted audiences. Patched versions 0.6.20 and 0.7.2 are available to remediate the exposure.

Technical ContextAI

Classified as CWE-862 (Missing Authorization). Affects the ActivityPub outbox component of Hollo. Hollo is a federated single-user microblogging software designed to be federated through ActivityPub. Prior to 0.6.20 and 0.7.2, there is a security vulnerability where DMs and followers-only posts were exposed through the ActivityPub outbox endpoint without authorization. This vulnerability is fixed in 0.6.20 and 0.7.2.