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CVE-2026-59563

HMAC Confirmation Token Unbinding in zscaler-mcp-server

No known exploitation. EPSS puts it in the 2nd percentile. Fixed in 0.7.2.

CVSS 3.14.6MediumEPSS percentile2nd0.1% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
No public exploit knownFix0.7.2Upgrade to this build

Published Updated Sources: CVE.org, NVD

NVD CVE.org

What to do

Find your product and version, then upgrade to the build on the right.

  • Zscaler-mcp-serverAffected: ≥ 0.7.0, < 0.7.2Upgrade to: 0.7.2Stated by: CVE record

Versions as the sources state them. Full version matrix after sign-in

What it is

From the CVE record

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.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS2nd
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

0.1% chance of exploitation activity in the next 30 days, which ranks it in the 2nd percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

3 events over 0 days, from the signal feeds we watch.

  1. Publishedweakness classified, record updated

Affected products

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:L

Scored 4.6 by NVD.

How it is reached

  • Attack Vector NetworkExploitable remotely over the network without any special conditions
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required LowRequires basic user-level privileges
  • User Interaction RequiredA user must click a link, open a file, or perform some action

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality NoneNo confidentiality impact
  • Integrity LowData modification is possible but limited in scope or consequence
  • Availability LowReduced performance or intermittent disruption of service

Weaknesses

Sources

References in the record

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