Remote User
        │
        ▼
Accessible Sidecar Endpoint
        │
        ▼
Create Arbitrary Files
        │
        ▼
Truncate Existing Files
        │
        ▼
System Impact

Attacker
    │
    ▼
Locate Exposed Splunk Service
    │
    ▼
Connect To PostgreSQL Sidecar
    │
    ▼
Unauthenticated Request
    │
    ▼
Create/Overwrite Files
    │
    ▼
Service Disruption
    │
    ▼
Potential Escalation

Potential exposure of sensitive operational data.

Arbitrary file modification can compromise system integrity.

Critical files may be truncated, causing outages.

SIEM infrastructure may become unreliable or unavailable.

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

8000
8089
8191
5432

http.title:"Splunk"

product:"Splunk"

http.html:"Splunk"

title="Splunk"

body="Splunk"

app="Splunk"

app:"Splunk"

File creation events
File truncation events
Service failures
Configuration changes
Database sidecar access

find /opt/splunk -mtime -1

find /opt/splunk -size 0

journalctl -xe

grep -Ri "postgres" /opt/splunk/var/log/

Unexpected empty files
Modified configuration files
Splunk restart anomalies
Unauthorized service access
Network connections to sidecar components

server.conf
inputs.conf
outputs.conf
authentication.conf
web.conf

1. Discover vulnerable Splunk instance
2. Reach PostgreSQL sidecar endpoint
3. Submit crafted request
4. Create or truncate target file
5. Observe system impact

10.2.4+
10.0.7+

VPN-only access
Internal management network
ACL restrictions
Firewall filtering

File creation activity
Configuration modifications
Unexpected service restarts

Management Interfaces
        │
        ├── Internal VLAN
        ├── VPN Access
        └── Zero Trust Controls

Auditd
Sysmon for Linux
EDR telemetry
Network monitoring

CVE-2026-20253/
│
├── README.md
│
├── assets/
│   ├── CVE-2026-20253.png
│   └── screenshots/
│
├── advisory/
│   ├── technical-analysis.md
│   ├── attack-surface.md
│   └── patch-guidance.md
│
├── detection/
│   ├── sigma/
│   ├── yara/
│   ├── splunk-searches/
│   └── hunting-guide.md
│
├── iocs/
│   └── indicators.md
│
└── references/
    └── links.md