CVE-2026-76353: Splunk Enterprise Privilege Escalation

CVE-2026-76353 Overview

CVE-2026-76353 is an authorization and path restriction flaw in Splunk Enterprise. A low-privileged user who does not hold the admin or power Splunk roles can submit a crafted knowledge bundle delta to a cluster manager. The malformed delta triggers arbitrary file deletion on paths accessible to the Splunk Enterprise process. The issue affects system integrity and can disrupt service on distributed search deployments. The vulnerability is tracked under [CWE-24] (path traversal involving file extension) and is documented in Splunk Security Advisory SVD-2026-0801.

Critical Impact
A non-admin, non-power Splunk user can remotely delete arbitrary files on a cluster manager, degrading search availability and cluster integrity.

Affected Products

Splunk Enterprise versions below 10.4.2
Splunk Enterprise versions below 10.2.6 and 10.0.9
Splunk Enterprise versions below 9.4.14

Discovery Timeline

2026-08-19 - CVE-2026-76353 published to the National Vulnerability Database
2026-08-20 - Last updated in NVD database

Technical Details for CVE-2026-76353

Vulnerability Analysis

Splunk Enterprise uses knowledge bundle replication to distribute configuration and knowledge objects from a search head or cluster manager to search peers. The bundle delta mechanism transmits incremental changes, including file removals, between the staging directory and target peers. The endpoint that accepts these deltas fails to enforce role-based authorization boundaries. It also fails to validate that file removal paths remain constrained to the staging directory.

An authenticated user without admin or power role membership can send a crafted knowledge bundle delta. The delta specifies file removal operations with paths that escape the intended staging directory. The cluster manager process then deletes files anywhere the Splunk service account has write access. Refer to the Knowledge bundle replication overview for background on the affected subsystem.

Root Cause

Two compounding defects create the flaw. First, the bundle delta processor does not canonicalize or restrict removal paths to the staging directory root. Second, the receiving endpoint does not verify that the caller holds the roles required to modify cluster-wide state. Together, these gaps allow a low-privileged authenticated user to trigger destructive filesystem operations.

Attack Vector

The attack requires network access to the cluster manager and valid Splunk credentials without elevated roles. The attacker crafts a knowledge bundle delta containing removal directives that reference files outside the staging directory. On submission, the cluster manager processes the delta and deletes the referenced files. The vulnerability is remotely exploitable over the network and requires low attack complexity. No user interaction is required beyond the attacker's own authenticated request.

No public proof-of-concept exploit is available at the time of publication.

Detection Methods for CVE-2026-76353

Indicators of Compromise

Unexpected file deletions in Splunk installation directories such as $SPLUNK_HOME/etc, $SPLUNK_HOME/var, or configuration bundle paths
Knowledge bundle replication errors, search peer synchronization failures, or missing knowledge objects reported by the cluster manager
Audit log entries showing knowledge bundle delta submissions from accounts that do not hold admin or power roles

Detection Strategies

Review audit.log and splunkd.log on cluster managers for bundle replication activity originating from unexpected user accounts
Correlate REST endpoint access records with the submitting user's role assignments to identify authorization boundary violations
Monitor filesystem integrity of $SPLUNK_HOME and staging directories to identify unauthorized deletions

Monitoring Recommendations

Enable verbose audit logging for distributed search and knowledge bundle operations on cluster manager instances
Forward Splunk internal logs and OS-level file deletion telemetry into a centralized SIEM for correlation
Alert on any bundle delta submissions from users outside the expected administrator group

How to Mitigate CVE-2026-76353

Immediate Actions Required

Upgrade Splunk Enterprise to a fixed release: 10.4.2, 10.2.6, 10.0.9, 9.4.14, or later
Audit Splunk role assignments and remove unnecessary user accounts from cluster manager access
Review recent bundle replication activity for unauthorized delta submissions and validate filesystem integrity

Patch Information

Splunk has released fixed versions addressing this vulnerability. Administrators should upgrade to Splunk Enterprise 10.4.2, 10.2.6, 10.0.9, 9.4.14, or higher. Details are published in Splunk Security Advisory SVD-2026-0801.

Workarounds

Restrict network access to cluster manager REST endpoints using firewall rules or network segmentation
Enforce least privilege on Splunk role assignments and remove non-essential accounts from any cluster interaction
Run the Splunk service account with the minimum filesystem permissions needed for normal operation to reduce blast radius

bash

# Verify Splunk Enterprise version on the cluster manager
$SPLUNK_HOME/bin/splunk version

# List users and their assigned roles for review
$SPLUNK_HOME/bin/splunk list user

# Restrict management port access to trusted administrator networks (example iptables rule)
iptables -A INPUT -p tcp --dport 8089 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 8089 -j DROP