High severity · published Sep 28, 2026
CVE-2026-55157
Token Optimizer MCP: OS command injection in smart_user via username in get-user-info
8.4
CVSS
0.9%
EPSS
No
On KEV
Description
Token Optimizer MCP measures token savings per AI coding agent, optimizes context, and shares a live local knowledge graph across 16 CLI clients. Prior to version 5.1.0, token-optimizer-mcp is vulnerable to OS command injection in the smart_user tool. Any MCP client that can call the smart_user tool can execute arbitrary shell commands through the username argument of the get-user-info operation. The commands execute with the privileges of the user running the token-optimizer-mcp server. This issue has been patched in version 5.1.0.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Local
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.9% · higher than 59% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
TO
token-optimizer-mcp · ooples
< 5.1.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-55157
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-55157
x_refsource_CONFIRM
https://github.com/ooples/token-optimizer-mcp/security/advisories/GHSA-49mq-fc6q-3h46
x_refsource_MISC
https://github.com/ooples/token-optimizer-mcp/commit/b4ee96dac799cbfba0a9f9c17844ce9d613cbcc7
x_refsource_MISC
https://github.com/ooples/token-optimizer-mcp/releases/tag/v5.1.0
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