Medium exploit reference

CVE-2026-90813 — cosmicstack-labs mercury-agent Shell Command Execution permissions.ts checkShellCommand validate before canonicalize

A vulnerability was detected in cosmicstack-labs mercury-agent up to 1.1.13. Affected is the function checkShellCommand of the file src/capabilities/permissions.ts of the component Shell Command Execution. The manipulation results in incorrect behavior order: validate before canonicalize. The attack may be launched remotely. The exploit is now public and may be used. The project was informed of the problem early through an issue report but has not responded yet.

Published Sep 14, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: VulDB

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

Technical severity (medium)+3
CISA SSVC: exploitation "poc"+5

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

—

No EPSS score.

Affects

Cosmicstack-labs

Mercury-agent

CVSS base

4.3

Medium · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

Proof of concept

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Cosmicstack-labs Mercury-agent).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Cosmicstack-labs	Mercury-agent	version 1.1.0version 1.1.1version 1.1.2version 1.1.3version 1.1.4version 1.1.5version 1.1.6version 1.1.7 and 6 more version 1.1.8version 1.1.9version 1.1.10version 1.1.11version 1.1.12version 1.1.13	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

Low

User interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
5.3	CVSS 4.0	Medium	—	—	VulDB via CVE Program (cve.org) e CISA ADP
2.1	CVSS 4.0	Low	—	—	cna@vuldb.com via NIST National Vulnerability Database
4.3	CVSS 3.1	Medium	2.8	1.4	cna@vuldb.com via NIST National Vulnerability Database
4.3	CVSS 3.1	Medium	—	—	VulDB via CVE Program (cve.org) e CISA ADP
4.3	CVSS 3.0	Medium	—	—	VulDB via CVE Program (cve.org) e CISA ADP
4.0	CVSS 2.0	Medium	8.0	2.9	cna@vuldb.com via NIST National Vulnerability Database
4.0	CVSS 2.0	Medium	—	—	VulDB via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N (score shown at the top: cna@vuldb.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-179

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).

web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

2026
Affected products added · cosmicstack-labs/mercury-agent
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 15, 2026
CVSS changed · 4.3
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · → Deferred
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Sep 14, 2026 · VulDB

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

6 on the record

github.com/cosmicstack-labs/mercury-agent/
product, NIST National Vulnerability Database
github.com/cosmicstack-labs/mercury-agent/issues/95
exploit, issue-tracking, NIST National Vulnerability Database
vuldb.com/submit/922879
third-party-advisory, NIST National Vulnerability Database
vuldb.com/vuln/403315
vdb-entry, technical-description, NIST National Vulnerability Database
vuldb.com/cve/CVE-2026-90813
third-party-advisory, NIST National Vulnerability Database
vuldb.com/vuln/403315/cti
signature, permissions-required, NIST National Vulnerability Database

Elsewhere on this site

Cosmicstack-labs
every CVE for this vendor

CWE-179
other pages naming this weakness

Related CVEs (same products)

Medium CVE-2026-90814 cosmicstack-labs mercury-agent GitHub API github.ts githubRequest server-side request forgery Sep 14, 2026
Medium CVE-2026-90812 cosmicstack-labs mercury-agent Shell Command Permission permissions.ts checkShellCommand privileges assignment Sep 14, 2026
Medium CVE-2026-90810 cosmicstack-labs mercury-agent Shell Command Permission Check permissions.ts PermissionManager.checkShellCommand improper authorization Sep 14, 2026
Low CVE-2026-90811 cosmicstack-labs mercury-agent Shell Permission Manifest permissions.ts PermissionManager.checkShellCommand information disclosure Sep 14, 2026
Medium CVE-2026-18998 cosmicstack-labs mercury-agent delegate_task Tool sub-agent.ts SubAgent.run improper authorization Aug 6, 2026
Medium CVE-2026-18996 cosmicstack-labs mercury-agent run_command permissions.ts PermissionManager.checkShellCommand privileges assignment Aug 6, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No FIRST EPSS score.
No fixed version, patch or mitigation documented.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-90813 is "cosmicstack-labs mercury-agent Shell Command Execution permissions.ts checkShellCommand validate before canonicalize", rated Medium. It affects Mercury-agent (Cosmicstack-labs); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 4.3 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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