External risk intelligence

Unauthenticated Webhook Message Injection and SSRF in Xiaobei

CVE advisorySeverity: CRITICAL (CVSS 9.3)

CVE-2026-85667

The vulnerability exists in a webhook endpoint designed to receive external messages. Webhook listeners are intended to be reachable from the internet to process incoming events, making this surface public-facing by design.

Missing Authentication

Halo Surface Signal: 5 out of 5 — more likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

This vulnerability affects the xiaobei technology, allowing unauthenticated attackers to inject arbitrary messages into the agent pipeline and potentially interact with internal services. The main concern is confirming relevance and exposure given the potential for unauthorized message injection and server-side request forgery.

Unauthenticated message injection is possible.
This could expose internal systems to risk.
Confirm if this technology is in use.

Attack Path

How an attacker could exploit the issue

Attackers can reach the vulnerable webhook endpoint over the network without any authentication. By sending specially crafted messages to this endpoint, an attacker can inject arbitrary content into the agent pipeline and potentially trick the system into fetching malicious content from internal services. This could lead to unauthorized actions or data exposure.

No authentication required.
Triggered by crafted webhook messages.
Risk of arbitrary code execution.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could allow unauthenticated attackers to send arbitrary messages into the agent pipeline by exploiting a lack of authentication and signature validation on webhook endpoints. It may also enable attackers to perform server-side request forgery against internal services through unvalidated media URL fetching.

Arbitrary messages injected into agent pipeline.
Unvalidated media URL fetching exploited.
Server-side request forgery against internal services.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in xiaobei impacts teams responsible for integrating external services and managing application security. The immediate priority is to locate all instances of the affected technology, confirm their exposure and business criticality, and identify the accountable product or platform owner. Remediation planning should then be based on a clear understanding of the associated risks.

Identify the accountable team.
Verify external reachability and criticality.
Plan phased remediation by risk.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is the xiaobei software used for?

Xiaobei is a software platform designed to manage and automate agent pipelines. It facilitates communication between external services and internal workflows by using webhook endpoints to ingest event data, process incoming messages, and trigger various automation tasks within a distributed system.

What does CVE-2026-85667 mean for system security?

This vulnerability is classified as Missing Authentication for Critical Function (CWE-306). It means the software fails to verify who is sending data to its webhook endpoints. Because there are no identity checks or message signatures, the system treats unauthorized requests as legitimate, allowing attackers to inject arbitrary messages or manipulate internal service interactions.

How is the vulnerability triggered by an attacker?

An attacker triggers the flaw by sending crafted payloads directly to the /webhook_worktool handler. The bug is triggered whenever the endpoint processes these unauthenticated requests. It is not triggered by internal traffic that originates from authenticated, verified sources, nor does it impact services that do not utilize the specific webhook integration.

Is my instance of xiaobei at risk?

According to Halo Surface Signal, this vulnerability is very likely to be reachable if your instance is public-facing. Because webhook listeners are designed to process external events, they are often exposed to the internet by default. If your xiaobei deployment can be reached from outside your private network, it is potentially susceptible to these unauthenticated requests.

How do I respond to this vulnerability?

Start by identifying all deployed instances of xiaobei within your environment and determining which are internet-facing. Coordinate with the product owners to assess the risk to connected internal systems. While planning for updates or security configurations, ensure that only trusted traffic can communicate with your webhook endpoints to prevent unauthorized injection or request forgery.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.