CVE-2026-59563

HMAC Confirmation Token Unbinding in zscaler-mcp-server

MEDIUM

4.6

CVSS Score

Published: September 28, 2026 at 12:54 PM UTC

Updated: September 28, 2026 at 03:17 PM UTC

1 product affected across 1 vendorMCP Server

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Severity

MEDIUM4.6

Exploit prediction

EPSS 0.1%

SSVC

No known exploit

Description

Zscaler MCP Server versions 0.7.0 and 0.7.1 has an issue where HMAC confirmation tokens were not bound to the target resource identifier, allowing an MCP client or agent to replay a token generated for one resource to affect another resource of the same type. This issue is fixed in version 0.7.2.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

MCP Server · Zscaler

60%

0.7.0 ≤ v < 0.7.20.7.0

Affected range stops below 0.7.2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (1)

Source: cverecord

https://github.com/zscaler/zscaler-mcp-server/pull/41

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.6MEDIUMZscaler

Attack Vector: NETWORK
Complexity: LOW
Privileges: LOW
User Interaction: REQUIRED
Scope: UNCHANGED
Confidentiality: NONE
Integrity: LOW
Availability: LOW

Vector?

Quick Info

StatusAWAITING ANALYSIS

CWE

CWE-305

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