CVE-2026-59563: CWE-305 Authentication bypass by primary weakness in Zscaler zscaler-mcp-server
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.
AI Analysis
Technical Summary
CVE-2026-59563 describes an authentication bypass vulnerability in Zscaler MCP Server versions 0.7.0 and 0.7.1. The flaw arises because HMAC confirmation tokens are not tied to the target resource identifier, enabling replay attacks where a token valid for one resource can be reused to affect a different resource of the same type. This weakness is classified under CWE-305 (Authentication Bypass by Primary Weakness). The vulnerability has a CVSS v3.1 score of 4.6 (medium severity) and is fixed in version 0.7.2.
Potential Impact
The vulnerability allows an attacker with some level of privileges (PR:L) to replay HMAC tokens across different resources, potentially causing unauthorized actions or changes on resources other than the intended target. The impact includes limited integrity loss and availability impact but no confidentiality loss. There are no known exploits in the wild.
Mitigation Recommendations
Upgrade Zscaler MCP Server to version 0.7.2 or later, where the issue is fixed by binding HMAC confirmation tokens to their specific resource identifiers. No other mitigation is indicated.
CVE-2026-59563: CWE-305 Authentication bypass by primary weakness in Zscaler zscaler-mcp-server
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.
CVSS v3.1
Score 4.6medium
Affected software
Zscaler
zscaler-mcp-server
pkg:github/zscaler-mcp-serverRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-59563 describes an authentication bypass vulnerability in Zscaler MCP Server versions 0.7.0 and 0.7.1. The flaw arises because HMAC confirmation tokens are not tied to the target resource identifier, enabling replay attacks where a token valid for one resource can be reused to affect a different resource of the same type. This weakness is classified under CWE-305 (Authentication Bypass by Primary Weakness). The vulnerability has a CVSS v3.1 score of 4.6 (medium severity) and is fixed in version 0.7.2.
Potential Impact
The vulnerability allows an attacker with some level of privileges (PR:L) to replay HMAC tokens across different resources, potentially causing unauthorized actions or changes on resources other than the intended target. The impact includes limited integrity loss and availability impact but no confidentiality loss. There are no known exploits in the wild.
Mitigation Recommendations
Upgrade Zscaler MCP Server to version 0.7.2 or later, where the issue is fixed by binding HMAC confirmation tokens to their specific resource identifiers. No other mitigation is indicated.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- Zscaler
- Date Reserved
- 2026-07-06T06:18:59.633Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6aba7026f7a7c54106c00b49
Added to database: 09/28/2026, 13:48:22 UTC
Last enriched: 09/28/2026, 14:03:07 UTC
Last updated: 09/29/2026, 02:50:35 UTC
Views: 16
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