CVE-2026-18998Public exploitNetwork attack vector

Authenticated workflow interruption via ignored tool restrictions

Published Aug 6, 2026 · Updated Aug 6, 2026

Improper authorization in Mercury Agent 1.1.0 through 1.1.12 allows remote authenticated users to halt sibling sub-agents via web chat. SubAgent.run passes the complete capabilities.getTools() registry into each child loop instead of enforcing delegate_task's allowedTools list, while stop_agent lacks an ownership check. Exploitation requires authenticated dashboard access and model-mediated task delegation; demonstrated impact is enumeration and termination of sibling work, affecting parallel-workflow integrity and availability.

CVSS severity6.3

Medium

EPSS probability0.21%

Next 30 days · Sep 16, 2026

Known exploitationUnconfirmed

Based on sourced intelligence

Hinoki checkNot available

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Summary

What happened

The record

CVE: CVE-2026-18998
Published: Aug 6, 2026
Updated: Aug 6, 2026

Vendor: Cosmic Stack
Product: Mercury Agent
Classifications: CWE-285, CWE-266

Attack vector: network
Privileges: authenticated

Timeline

How it unfolded

Aug 6, 2026CVE publishedPublication date reported by the CVE source.
Aug 6, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

Affected versionversion=1.1.0
Affected versionversion=1.1.1
Affected versionversion=1.1.10
Affected versionversion=1.1.11
Affected versionversion=1.1.12
Affected versionversion=1.1.2
Affected versionversion=1.1.3
Affected versionversion=1.1.4
Affected versionversion=1.1.5
Affected versionversion=1.1.6
Affected versionversion=1.1.7
Affected versionversion=1.1.8
Affected versionversion=1.1.9

What conditions does exploitation require?

Attack vectornetwork

Required privilegesauthenticated

What is affected?

Cosmic Stack · Mercury Agentversion=1.1.0; version=1.1.1; version=1.1.10; version=1.1.11; version=1.1.12; version=1.1.2; version=1.1.3; version=1.1.4; version=1.1.5; version=1.1.6; version=1.1.7; version=1.1.8; version=1.1.9

Published CVSS scores

2.1VulDBCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P

6.5VulDBAV:N/AC:L/Au:S/C:P/I:P/A:P

6.3VulDBCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026

Latest reporting daySep 16, 2026

Latest daily unique IPsUnavailable

Prior 30-day averageUnavailable

SourceShadowserver honeypots (KEV)

Vectornetwork

Privilegesauthenticated

Known exploitationUnconfirmed

Public exploitPublished

Weakness, pattern, technique

CWE-285Improper Authorization

CWE-266Incorrect Privilege Assignment

Public exploit references

verification_test.py restricted-child orchestration PoCfunctional · demonstrated

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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