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CVE-2026-20253 Splunk CVE debrief

A critical vulnerability, CVE-2026-20253, was found in Splunk Enterprise versions below 10.2.4 and 10.0.7, and Splunk Cloud Platform versions below 10.4.2604.3 and 10.2.2510.14. This vulnerability allows an unauthenticated user to create or truncate arbitrary files through a PostgreSQL sidecar service endpoint. The issue arises from the lack of authentication controls in the PostgreSQL sidecar service endpoint, making it possible for any network-reachable user to invoke file operations without credentials. The CVSS score for this vulnerability is 9.8, indicating a critical severity level.

Vendor
Splunk
Product
Splunk Enterprise
CVSS
CRITICAL 9.8
CISA KEV
Listed
Original CVE published
2026-06-18
Original CVE updated
2026-06-18
Advisory published
2026-06-18
Advisory updated
2026-06-18

Who should care

Users of Splunk Enterprise and Splunk Cloud Platform should be aware of this vulnerability, especially those with versions below the specified thresholds.

Technical summary

The vulnerability exists in the PostgreSQL sidecar service endpoint, which lacks authentication controls. This allows unauthenticated users to create or truncate arbitrary files.

Defensive priority

High

Recommended defensive actions

  • Upgrade Splunk Enterprise to version 10.2.4 or 10.0.7, or later.
  • Upgrade Splunk Cloud Platform to version 10.4.2604.3 or 10.2.2510.14, or later.
  • Refer to [ref-4](https://advisory.splunk.com/advisories/SVD-2026-0603) for more information and patching guidance.

Evidence notes

The vendor is identified as 'Unknown Vendor' with low confidence, based on evidence from 'reference_domain_candidate' suggesting 'Splunk'.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-20253 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-20253

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

  • CVE-2026-20253 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-20253

    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.