Is this vulnerability remotely exploitable?

Yes, in typical deployments it is remotely exploitable by any party that can reach the ActivityPub outbox endpoint, including remote federated instances or unauthenticated network clients, depending on the instance configuration.

What level of access does an attacker need to exploit this?

An attacker generally only needs network access to the Hollo instance's ActivityPub outbox endpoint. They do not need to be a follower, DM participant, or even an authenticated local user if the endpoint is exposed without additional protection.

What is the safest general fix pattern for this issue?

The safest pattern is to enforce consistent, centralized authorization on all outbox responses: for each activity, verify that the requesting principal is allowed to view it based on its visibility (public, followers-only, direct) and the relationship between requester and author. Non-public content should be excluded unless explicitly authorized.

Severity:

HIGH RISK

(7.5)

Missing Authorization on ActivityPub Outbox (CWE-862) in Hollo Federated Microblogging

CVE-2026-25808

Published:

Feb 9, 2026

Status:

Analyzed

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

NDV

Recent Vulnerabilities

CWE-77;CWE-78

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setGameSpeedCfg CGI Handler

Remote Code Execution on the Router

April 6, 2026

CWE-77;CWE-78

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setFirewallType Handler

Remote Code Execution on Router Firmware

April 6, 2026

Vulnerability Type

Category:

Missing Authorization

CWE:

CWE-862

Impact:

Exposure of Sensitive Private Messages and Restricted Posts

Severity:

HIGH RISK

(7.5)

CVSS Version:

3.1

Vulnerability Type

Category:

Missing Authorization

CWE:

CWE-862

Impact:

Exposure of Sensitive Private Messages and Restricted Posts

Severity:

HIGH RISK

(7.5)

CVSS Version:

3.1

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Ask AI for summary of CodeAnt

Missing Authorization on ActivityPub Outbox (CWE-862) in Hollo Federated Microblogging

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

Recent Vulnerabilities

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setGameSpeedCfg CGI Handler

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setFirewallType Handler

Vulnerability Type

Vulnerability Type

Vulnerability Type

Catch This CVE While Code Is Being Written

Ship clean & secure code faster

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