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PatchSiren cyber security CVE debrief

CVE-2026-20255 Splunk CVE debrief

A vulnerability was found in Splunk Enterprise and Splunk Cloud Platform. The issue allows a low-privileged user to craft a malicious classic dashboard that can exfiltrate sensitive data to an external server. This is possible due to incomplete URL validation on the external content dialog, which can allow requests to untrusted domains when a user interacts with a crafted dashboard.

Vendor
Splunk
Product
Splunk Enterprise
CVSS
MEDIUM 5.7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-10
Original CVE updated
2026-06-15
Advisory published
2026-06-10
Advisory updated
2026-06-15

Who should care

Administrators and users of Splunk Enterprise versions below 10.2.4, 10.0.7, 9.4.12, and 9.3.13, and Splunk Cloud Platform versions below 10.3.2512.13, 10.2.2510.15, 10.1.2507.23, and 9.3.2411.132 should be aware of this vulnerability.

Technical summary

The vulnerability exists in Splunk Enterprise and Splunk Cloud Platform due to incomplete URL validation on the external content dialog. This allows a low-privileged user, who does not hold the 'admin' or 'power' Splunk roles, to craft a malicious classic dashboard. When interacted with, this dashboard can exfiltrate sensitive data to an external server.

Defensive priority

MEDIUM

Recommended defensive actions

  • Update Splunk Enterprise to version 10.2.4, 10.0.7, 9.4.12, or 9.3.13, or later.
  • Update Splunk Cloud Platform to version 10.3.2512.13, 10.2.2510.15, 10.1.2507.23, or 9.3.2411.132, or later.
  • Restrict access to sensitive data and dashboards.
  • Monitor dashboard interactions for suspicious activity.

Evidence notes

The CVE-2026-20255 vulnerability was found in Splunk Enterprise and Splunk Cloud Platform. The Common Vulnerability Scoring System (CVSS) score is 5.7, indicating a medium severity.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-20255 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-20255

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-20255 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-20255

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.