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Cyber News & CTI Reports :: 2026-06-13 | Critical Splunk Enterprise Flaw Lets Attackers Run Code Without Authentication
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2026-06-13 | Critical Splunk Enterprise Flaw Lets Attackers Run Code Without Authentication

1. AI Summary

Splunk released security updates to fix a critical vulnerability (CVE-2026-20253) in Splunk Enterprise. This flaw allows unauthenticated users to perform arbitrary file operations and achieve remote code execution (RCE) via PostgreSQL sidecar service endpoints. Attackers can leverage /backup and /restore endpoints to write malicious Python scripts to the file system.

2. IOCs

IOC Type Value Description Relevant MITRE ATT&CK Techniques
Filepath
/opt/splunk/etc/apps/splunk_secure_gateway/bin/ssg_enable_modular_input.py
Python script target for overwriting to achieve remote code execution T1059.006
Filepath
/opt/splunk/var/packages/data/postgres/.pgpass
File containing credentials for the postgres_admin user used during the restore process T1555
Vulnerability CVE-2026-20253 Critical flaw in Splunk Enterprise allowing unauthenticated file operations and RCE T1190

3. MITRE ATT&CK

Code Title
T1190 Exploitation of Remote Services via unauthenticated endpoints /v1/postgres/recovery/backup and /v1/postgres/recovery/restore
T1059.006 Command and Scripting Interpreter: Python script overwriting for RCE
T1565.001 Data Manipulation: Overwriting system files to achieve code execution
T1210 Exploitation of Remote Services: Utilizing PostgreSQL sidecar service to write arbitrary files

4. Targets

Type Value
Company Splunk Enterprise users
Sector Enterprise software users

5. Article Details

6. Original text

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 files through a PostgreSQL sidecar service endpoint," Splunk said in an alert this week. "The vulnerability exists because the PostgreSQL sidecar service endpoint lacks authentication controls, allowing any network-reachable user to invoke file operations without credentials." The issue has been addressed in the following versions - Splunk Enterprise 10.0.0 to 10.0.6 - Fixed in 10.0.7 Splunk Enterprise 10.2.0 to 10.2.3 - Fixed in 10.2.4 Splunk Enterprise 10.4 - Not affected Splunk, which is part of Cisco, said Splunk Cloud is not impacted by the vulnerability as Postgres sidecars are not used in the product. What the Flaw is All About On Friday, watchTowr Labs released additional technical details of
CVE-2026-20253
, stating it could be exploited to achieve pre-authenticated remote code execution on susceptible systems through the "/v1/postgres/recovery/backup" and "/v1/postgres/recovery/restore" endpoints.

The attack chain works as follows - Connect to an attacker-controlled database and dump its contents into an arbitrary file using the /backup endpoint Load the dump of the attacker-controlled database into the local PostgreSQL instance using the /restore endpoint by including a "passfile" argument that specifies the path to a " .pgpass " file ("

/opt/splunk/var/packages/data/postgres/.pgpass
") containing the password for the "postgres_admin" user SQL queries defined in the database dump will get executed by Splunk's PostgreSQL instance An attacker could weaponize this weakness to define a new function that uses lo_export - a function used to extract a BLOB from the database and save it as a file on the file system - to write attacker-controlled content to a file, following which the function gets executed during the restoration process. "At this point, we can authenticate, restore attacker-controlled SQL, and interact with the local database," security researchers Piotr Bazydlo and Yordan Ganchev said. "Once we could restore attacker-controlled SQL into the local PostgreSQL instance, we quickly put together a database dump template that gave us a controlled file write." Armed with an arbitrary file write primitive on the Splunk file system, an attacker could escalate further to remote code execution by overwriting a Python script that Splunk frequently executes (e.g., "
/opt/splunk/etc/apps/splunk_secure_gateway/bin/ssg_enable_modular_input.py
") to include the malicious payload.

The entire sequence of actions is below - Create a database and configure it such that a user can authenticate without a password and grant it sufficient permissions to invoke functions like lo_export Use the /backup endpoint to drop a dump of the remote database onto the Splunk file system Use the /restore endpoint to load the malicious database dump, trigger execution of the malicious function during the restore process, and write an attacker-controlled Python script to the Splunk file system Although there is no evidence of the flaw being exploited in the wild, the availability of the exploit specifics can be enough to drive threat actors to trigger opportunistic attempts. It's essential that users move quickly to apply the fixes to stay protected.