Splunk MCP Server: Insertion of Sensitive Information into Log File
CVE-2026-20205 is a high-severity insertion of sensitive information into log file vulnerability in Splunk MCP Server from Splunk, with a CVSS 3.1 base score of 7.2 out of 10. It can be exploited remotely over the network by an attacker with administrator privileges, without any action from a user. The record lists version 1.0.3 as the first without the flaw, so updating Splunk MCP Server to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.29% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Splunk MCP Server to 1.0.3 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Splunk | Splunk MCP Server | 1.0 up to, but not including, 1.0.3 | 1.0.3 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- HighAdministrator-level access is required first.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (cisco.com).
Official description
In Splunk MCP Server app versions below 1.0.3 , a user who holds a role with access to the Splunk `_internal` index or possesses the high-privilege capability `mcp_tool_admin` could view users session and authorization tokens in clear text.<br><br>The vulnerability would require either local access to the log files or administrative access to internal indexes, which by default only the admin role receives. <br><br>Review roles and capabilities on your instance and restrict internal index access to administrator-level roles. See [Define roles on the Splunk platform with capabilities](https://docs.splunk.com/Documentation/Splunk/latest/Security/Rolesandcapabilities) and [Connecting to MCP Server and Admin settings](https://help.splunk.com/en/splunk-enterprise/mcp-server-for-splunk-platform/connecting-to-mcp-server-and-admin-settings) in the Splunk documentation for more information.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Insertion of Sensitive Information into Log File
The product writes sensitive information to a log file.
How developers prevent this class of flaw
- Consider seriously the sensitivity of the information written into log files. Do not write secrets into the log files.
- Remove debug log files before deploying the application into production.
- Protect log files against unauthorized read/write.
More Insertion of Sensitive Information into Log File vulnerabilities (CWE-532)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Recent Insertion of Sensitive Information into Log File vulnerabilities
- 7.5 High severity
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- 7.3 High severity
- 7.5 High severity
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