Vulnerability report

Active exploitation observed Confirmed confidence In CISA KEV

CVE-2026-20253

Splunk Enterprise

Splunk Enterprise · affected before 10.2.4

Watch CVE-2026-20253 Browse KEV feed
Severity
CVSS 9.8 · Critical
Confidence
Confirmed
Exploit status
Observed in sensors
EPSS
96.9%
First observed
12 Jun 2026
Last observed
12 Oct 2026

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2026-20253 is an unauthenticated vulnerability affecting Splunk Enterprise. 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...

Is it exploited?

Yes. Previdian sensors observed exploitation attempts with confirmed confidence. Listed in CISA KEV. Also confirmed by third-party sources.

Who is affected?

Splunk Enterprise affected before 10.2.4.

What should we do?

Patch immediately, validate internet-facing exposure, and monitor for matching requests.

Overview

Splunk Enterprise

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.

Splunk Affected
Splunk Enterprise
Before 10.2.4 Before 10.0.7
Published
10 Jun 2026
Exploited Since
12 Jun 2026
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

postgresql nuclei_scanner cisa

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

Previdian

Recorded 15 Jun 2026

Previdian independently recorded this as exploited after first seeing it in honeypot sensors.

Active exploitation observed

Previdian sensor

First observed 15 Jun 2026

Previdian first observed exploitation attempts targeting this vulnerability in our honeypot sensors.

Proof of concept available

GitHub

Recorded 12 Jun 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
Previdian Sensors First 2026-06-15 05:15 UTC
CISA 2026-06-18 00:00 UTC
CVE 2026-06-18 17:41 UTC
Daily CyberSecurity 2026-06-18 18:20 UTC
All CISA Advisories 2026-06-18 18:20 UTC
The Shadowserver 2026-07-09 00:00 UTC

Operational indicators for this CVE are listed under Detection.

Sensor telemetry

First-party evidence of exploitation activity

Previdian sensors recorded exploitation attempts targeting this vulnerability. The cards and chart show volume, unique attackers, and daily activity.

162

Attempts observed

23

Unique attacker IPs

9

Attacker countries

CA · CN · ES · JP · NL · NO · SE · SG · US

2

Sensors observed

CVE-2026-20253 exploitation attempts over the last 82 days

Daily events observed by Previdian sensors

Updated 18 Oct 2026

0
26
0
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34
0
0
0
0
0
1
1
0
17
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0
0
0
0
0
0
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0
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20
1
1
0
0
0
0
0
0
5
1
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8
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6
0
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0
0
0
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11
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17
0
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2
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3
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0
29 Jul 15 Aug 1 Sep 18 Sep 18 Oct

First observed 12 Jun 2026 · Last observed 12 Oct 2026

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Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
3
3
2

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Virtual patch status

Previdian virtual patch guidance is available for this CVE.

AWS WAF Cloudflare ModSecurity

Attacker IP Indicators

Attacker IP indicators observed · available in Pro and Enterprise.

Sensor-derived attacker IP indicators are available to Pro and Enterprise accounts under Detection and through the Pro API.

Learn about Pro API access

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-20253.yaml 15 Jun 2026

Virtual Patch Detail

Compensating WAF rules for this CVE.

Available

Enterprise feature. Virtual patch rule content and deployable vendor exports (ModSecurity, Cloudflare, AWS WAF) are available to Previdian Enterprise users.

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Risk and context

Severity, weaknesses, and research context

CVSS v3.1

9.8 Critical

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

96.9%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Missing Authentication for Critical Function CWE-306

Recent mention · SOCRadar

Top RCE Vulnerabilities

Top RCE Vulnerabilities A remote code execution (RCE) vulnerability is a software flaw that lets an attacker run their own code on a target system from a remote location. Exploiting vulnerabilities like this is now the m

Read full advisory

All Mentions

Recent mention · SOCRadar

Top RCE Vulnerabilities

SOCRadar · 14 Oct 2026

Top RCE Vulnerabilities A remote code execution (RCE) vulnerability is a software flaw that lets an attacker run their own code on a target system from a remote location. Exploiting vulnerabilities like this is now the m

Recent mention · Daily CyberSecurity

Splunk CVE-2026-20253: CVSS 9.8 RCE Exploited in the Wild

Daily CyberSecurity · 18 Jun 2026

  The cybersecurity landscape faces a critical threat today. CISA confirmed active exploitation of Splunk CVE-2026-20253. Consequently, administrators The post Splunk CVE-2026-20253: CVSS 9.8 RCE Exploited in the Wild appeared first on Daily CyberSecurity.

Recent mention · All CISA Advisories

CISA Adds One Known Exploited Vulnerability to Catalog

All CISA Advisories · 18 Jun 2026

CISA has added one new vulnerability to its Known Exploited Vulnerabilities (KEV) Catalog, based on evidence of active exploitation. CVE-2026-20253 Splunk Enterprise Missing Authentication for Critical Function Vulnerability This type of vulnerability is a frequent attack vector for malicious cyber actors and poses significant risks to the federal enterprise. Binding Operational Directive (BOD) 26-04: Prioritizing Security Updates Based on Risk establishes vulnerability management requirements for Federal Civilian Executive Branch (FCEB) agencies, updating BOD 22-01. BOD 26-04 reinforces...

Recent mention · The Hacker News

Critical Splunk Enterprise Flaw Lets Attackers Run Code Without Authentication

The Hacker News · 13 Jun 2026

Splunk has released security updates to address a critical security flaw in Splunk Enterprise that could be exploited to conduct unauthenticated file operations and even remote code execution. The vulnerability, tracked as CVE-2026-20253, is rated 9.8 on the CVSS scoring system. "In Splunk Enterprise versions below 10.2.4 and 10.0.7, an unauthenticated user could create or truncate arbitrary

Recent mention · watchTowr

Why Use App-Level Auth When Every Database Has Auth? (Splunk Enterprise CVE-2026-20253 Pre-Auth RCE)

watchTowr · 12 Jun 2026

Three posts? In three days? Are we insane?We're home alone, there's no one to stop us, and we're up past bedtime. So, we need to talk about Splunk. On June 10th, Splunk published this CVE-2026-20253 advisory:It has everything that we

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

Unauthenticated arbitrary file operations in Splunk Enterprise PostgreSQL sidecar service (SVD-2026-0603)

pruva · Created 2026-07-07 21:08:36 UTC

Severity: CRITICAL | CVE: CVE-2026-20253 | Package: splunk/splunk

Splunk Enterprise & Cloud Platform - Unrestricted File Upload

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation

  1. 00:00 UTC

    KEV confirmed by The Shadowserver

    Exploitation attested by an external source

  2. 13:49 UTC

    Virtual patch available

    Compensating WAF rule available to block exploitation

  3. 18:20 UTC

    KEV confirmed by All CISA Advisories

    Exploitation attested by an external source

  4. 18:20 UTC

    KEV confirmed by Daily CyberSecurity

    Exploitation attested by an external source

  5. 17:41 UTC

    KEV confirmed by CVE

    Exploitation attested by an external source

  6. 00:00 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  7. 05:15 UTC

    Indicators of compromise added (81)

    Indicators of compromise recorded

  8. 05:15 UTC

    Observed by Previdian sensors

    Evidence-backed exploitation signal

  9. 04:30 UTC

    Public PoC available

    Public proof-of-concept code published

  10. 04:30 UTC

    Nuclei template available

    Scanner coverage available

  11. 17:16 UTC

    CVE published

    Vulnerability disclosed publicly

  12. 11:59 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2026-20253

Sample API response 
{
  "cve_id": "CVE-2026-20253",
  "confidence": "Confirmed",
  "cvss_score": 9.8,
  "cvss_estimated": false,
  "epss_score": 0.96939,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 162, "sensors": 2 }
}