cosmicstack-labs mercury-agent Shell Command Execution permissions.ts checkShellCommand validate before canonicalize

published 2026-09-14 55 d ago modified 2026-09-14 55 d ago also EUVD-2026-77773

cvss: 4.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 46%
public exploits: 0; none known

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.

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 55 d ago (2026-09-14)

Exploit prediction

0.55% chance of exploitation in the next 30 days, higher than 46% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/cosmicstack-labs/mercury-agent/issues/95 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	5.3	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P
CNA	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N/E:P/RL:X/RC:R
CNA	3.0	4.3	CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N/E:P/RL:X/RC:R
CNA	2.0	4.0	AV:N/AC:L/Au:S/C:P/I:N/A:N/E:POC/RL:ND/RC:UR
CNA	4.0	2.1	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
CNA	2.0	4.0	AV:N/AC:L/Au:S/C:P/I:N/A:N

Affected products

cosmicstack-labs mercury-agent

Classification

Weakness

CWE-180 Incorrect Behavior Order: Validate Before Canonicalize
CWE-179 Incorrect Behavior Order: Early Validation

References

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

Sources

CVE List CVE-2026-90813
NVD CVE-2026-90813

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary