CVEs / CVE-2026-20253
CVE-2026-20253: Splunk Enterprise Missing Authentication for Critical Function Vulnerability
- Known exploited in the CISA KEV catalog since 18 Jun 2026
- critical 9.8 CVSS 3.1 (from the CNA)
- EPSS 96.9% chance of exploitation in the next 30 days, higher than 99% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
Splunk Enterprise contains a missing authentication for critical function vulnerability which could allow an unauthenticated user to create or truncate arbitrary files through a PostgreSQL sidecar service endpoint.
Description
In Splunk Enterprise 10.2 versions below 10.2.4 and 10 versions below 10.0.7, an unauthenticated user could create or truncate arbitrary files through a PostgreSQL sidecar service endpoint. The vulnerability exists because the PostgreSQL sidecar service endpoint lacks authentication controls, allowing any network-reachable user to invoke file operations without credentials. Splunk Enterprise versions 9.4 and earlier are not affected. If you cannot immediately upgrade to a fixed version, you can mitigate this vulnerability by disabling the PostgreSQL sidecar service.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| Splunk Splunk Enterprise | from 10.2, before 10.2.4 | 10.2.4 |
| Splunk Splunk Enterprise | from 10.0, before 10.0.7 | 10.0.7 |
Exploitation
| In CISA KEV since | 18 Jun 2026 |
|---|---|
| Due date for US federal agencies | 21 Jun 2026 |
| Used in ransomware campaigns | Unknown |
| Required action | Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. |
Severity
| CVSS 3.1 | 9.8 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HScored by the CNA ([email protected]) |
|---|---|
| Weakness | CWE-306 |
References
- CVE-2026-20253 on NVD
- CVE-2026-20253 in the CISA KEV catalog
- https://advisory.splunk.com/advisories/SVD-2026-0603 (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk (cited by CISA)
- https://advisory.splunk.com/advisories/SVD-2026-0603 Mitigation, Vendor Advisory
- https://labs.watchtowr.com/why-use-app-level-auth-when-every-database-has-auth-splunk-enterprise-cve-2026-20253-pre-auth-rce/ Exploit, Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20253 US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.