Exploited CVEs / CVE-2026-20253
CVE-2026-20253
Splunk Enterprise Missing Authentication for Critical Function Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted. Federal agencies were required to remediate by 2026-06-21 (that deadline has passed); treat that date as the outer bound for your own environment. Check the vendor security advisory for the fix.
Actively exploited Splunk Enterprise vulnerability, Critical severity, CVSS 9.8. Added to the CISA KEV catalog 2026-06-18.
Risk summary
Updated July 26, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.
Senserva AI Opinion for CVE-2026-20253
This flaw lets an unauthenticated attacker create or truncate arbitrary files by hitting a PostgreSQL sidecar service endpoint in Splunk Enterprise, meaning no credentials are needed to corrupt or plant files on the host. With CISA KEV confirming active exploitation since 2026-06-18 and a 96% EPSS score, this is not theoretical, and any internet-reachable Splunk Enterprise deployment is a live target. File truncation against a SIEM is especially damaging because it can destroy the very logs you would use to detect an intrusion.
Do this: Identify all Splunk Enterprise instances, apply Splunk's fixed release immediately, and restrict network access to the PostgreSQL sidecar endpoint until patched.
AI-generated from public data, 2026-07-25. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2026-20253
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for CVE-2026-20253
Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.
CISA required action
Federal (BOD 22-01) remediation due date: 2026-06-21 (past due).
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.
Official fix for CVE-2026-20253
Check the vendor's security advisory channel for the patched Enterprise versions and workarounds.
Common questions about CVE-2026-20253
Is CVE-2026-20253 actively exploited?
Yes. CVE-2026-20253 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2026-06-18, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 96%.
What is the CISA deadline and required action for CVE-2026-20253?
CISA set the federal (BOD 22-01) remediation due date at 2026-06-21, which has passed; treat any unremediated system as overdue. The verbatim 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.
What fixes CVE-2026-20253?
Check the vendor's security advisory for the patched Enterprise versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.
Can I ask my own AI about CVE-2026-20253?
Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2026-20253's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed twice a day (5 AM and 3 PM US Central).
Authoritative references
Every actively exploited CVE, searchable with due dates and CSV export: the exploited-CVE tracker. The newest additions: exploited this week.
