CVE-2026-20253

Splunk Enterprise: Missing Authentication for Critical Function

As of , CVE-2026-20253 in Splunk Enterprise is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch this week.

Exploited
Yes: CISA listed it on 18 June 2026
US federal deadline
21 June 20263 days after CISA listed it. US federal civilian agencies must fix it by then.
Used in ransomware campaigns
Not known to CISA
EPSS score
0.97Higher than 99% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
Public exploit
None foundNeither Metasploit nor Exploit-DB lists one.
Fix
Vendor advice: advisory.splunk.comLinks below, from CISA's entry.

What CISA says to do

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.

CISA's required action

What the flaw is

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.

CISA's 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.

The CVE record's description, from cisco

CVE published
10 June 2026
Assigned by
cisco
CVSS
9.8 Critical (CVSS 3.1, from the CNA)
CWE-306
Missing Authentication for Critical Function
CISA SSVC, exploitation
active
CISA SSVC, automatable
yes
CISA SSVC, technical impact
total

Timeline

  1. The CVE record was published.
  2. CISA added it to its list of exploited vulnerabilities.
  3. The US federal deadline to fix it.

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