CVE-2025-20300 is a medium-severity vulnerability affecting multiple versions of Splunk Enterprise (below 9.4.2, 9.3.5, 9.2.6, and 9.1.9) and Splunk Cloud Platform (below 9.3.2411.103, 9.3.2408.112, and 9.2.2406.119). The vulnerability arises from an improper authorization check when a user attempts to access or perform certain actions on resources, specifically related to alert suppression functionality. In this case, a low-privileged user who does not hold the "admin" or "power" roles but has read-only access to a specific alert can exploit this flaw to suppress that alert when it triggers. This bypasses intended access restrictions, allowing unauthorized modification of alert behavior. The vulnerability does not affect confidentiality or availability directly but impacts the integrity of alerting mechanisms, potentially allowing attackers or malicious insiders to hide or delay detection of suspicious activities by suppressing alerts. The CVSS 3.1 score is 4.3 (medium), reflecting low complexity (AC:L), network attack vector (AV:N), and requiring low privileges (PR:L) but no user interaction (UI:N). No known exploits are currently reported in the wild. The issue is relevant for organizations relying on Splunk Enterprise or Cloud for security monitoring and alerting, as it undermines trust in alert notifications and could facilitate stealthy attacks or insider threats by hiding critical alerts from security teams.

For European organizations, this vulnerability could degrade the effectiveness of security monitoring and incident response processes that depend on Splunk alerts. Attackers or malicious insiders with low-level access could suppress alerts related to suspicious or malicious activities, delaying detection and response. This increases the risk of prolonged undetected breaches, data exfiltration, or other malicious actions. Organizations in regulated sectors such as finance, healthcare, and critical infrastructure, which often rely on Splunk for compliance and security monitoring, may face increased risk of non-compliance and operational impact. The integrity of security alerts is crucial for timely threat detection; thus, this vulnerability could weaken overall security posture and increase exposure to advanced persistent threats (APTs) or insider attacks.

1. Upgrade Splunk Enterprise and Splunk Cloud Platform to the fixed versions: 9.4.2 or later for Enterprise, and 9.3.2411.103 or later for Cloud Platform, as applicable. 2. Review and tighten role-based access controls (RBAC) to minimize read-only access to alerts for low-privileged users, especially those without admin or power roles. 3. Implement monitoring and auditing of alert suppression actions to detect unusual or unauthorized suppression activities. 4. Use Splunk’s alerting and logging features to create secondary alerts or notifications when alert suppression settings are modified. 5. Conduct regular security reviews and penetration testing focused on authorization controls within Splunk environments. 6. Educate security teams about this vulnerability to increase awareness and encourage verification of alert integrity during investigations.