CVE-2026-76267 in Splunk
Summary
by MITRE • 10/07/2026
In Splunk Enterprise versions below 10.4.3, 10.2.7, and 10.0.10, a user that holds a role with the read_o11y_content capability could inject forged entries into the app log through the Representational State Transfer (REST) API. The vulnerability is possible because Splunk App for Splunk O11y Cloud does not neutralize user-supplied SignalFlow content before writing it to the app log.
Splunk Enterprise versions 9.4.x are not affected.
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Analysis
by VulDB Data Team • 10/07/2026
The identified security flaw resides within specific legacy releases of Splunk Enterprise, namely those prior to version 10.4.3, 10.2.7, and 10.0.10. This vulnerability specifically impacts the interaction between users possessing the read_o11y_content capability and the underlying logging mechanisms of the Splunk App for Splunk O11y Cloud. The core technical deficiency is a failure to properly sanitize or neutralize user-supplied content within SignalFlow queries before these inputs are persisted into application log files via the Representational State Transfer API. By allowing unvalidated data entry directly into log structures, the system creates an avenue for attackers to manipulate internal logging processes through crafted HTTP requests that exploit this lack of input validation.
From a technical perspective, this issue classifies as CWE-117 Improper Output Neutralization for Logs, which is a subset of injection vulnerabilities where untrusted data is written to log files without adequate escaping or encoding. The attacker leverages the read_o11y_content permission set, which grants access to observability content, to submit maliciously constructed SignalFlow commands through the REST API interface. Because the application does not filter special characters or control sequences within these inputs before logging them, an authenticated user can inject arbitrary text into the log files. This behavior mirrors CWE-74 Improper Neutralization in XML Enhanced Environments and potentially CWE-1389 Malicious Log Injection, depending on how the injected content is subsequently processed by downstream systems that consume these logs for monitoring or forensic analysis.
The operational impact of this vulnerability extends beyond simple data corruption within the application itself. If log files are forwarded to a centralized logging platform such as Splunk Enterprise Security or other SIEM solutions, the forged entries could trigger false positive alerts, disrupt automated incident response workflows, or even lead to command injection if those downstream systems execute commands based on parsed log fields. Furthermore, an attacker with this level of access can potentially obscure their own malicious activities by injecting noise into the logs, thereby complicating forensic investigations and audit trails. This undermines the integrity of security monitoring capabilities that rely on accurate and untampered log data to detect threats effectively.
To mitigate this risk, organizations running affected versions must prioritize immediate patching to one of the fixed releases: Splunk Enterprise 10.4.3, 10.2.7, or 10.0.10. These updates include code changes that enforce strict input validation and proper encoding of SignalFlow content before it is written to any log file. Until patching can be implemented, administrators should review the principle of least privilege by auditing which users hold the read_o11y_content capability and restricting this role to only those individuals who absolutely require access to observability data. Additionally, implementing web application firewall rules that inspect REST API payloads for suspicious patterns in SignalFlow queries may provide a temporary layer of defense against exploitation attempts while infrastructure updates are being deployed.