Overview
CVE-2026-15143 is a critical vulnerability found in the file_type content detector of guardrails-detectors. This vulnerability allows a remote attacker to supply an arbitrary XML Schema Definition (XSD) string, which is processed without proper restrictions. This can lead to server-side requests to arbitrary URLs or local file reads, potentially resulting in sensitive information disclosure, such as cloud provider credentials or access to internal network services.
Understanding the Vulnerability / Threat
Root Cause Analysis
The fundamental flaw in CVE-2026-15143 is the lack of proper restrictions on the XML Schema Definition (XSD) string processing. This vulnerability belongs to the CWE-918 category, which involves server-side request forgery (SSRF).
Attack Surface & Vector
The vulnerability lives in the file_type content detector of guardrails-detectors. An attacker can reach this vulnerability through a network-adjacent or remote unauthenticated attack vector. The preconditions needed are minimal, as the attacker only needs to supply an arbitrary XSD string.
Exploitation Mechanics — Scenario Walkthrough
Scenario: Compromising a Corporate Red Hat OpenShift AI Instance
1. Initial Position: The attacker has remote access to the Red Hat OpenShift AI instance.
2. Triggering the Flaw: The attacker crafts a malicious XSD string and supplies it to the file_type content detector of guardrails-detectors. This string is processed without proper restrictions, allowing the attacker to make server-side requests to arbitrary URLs or read local files.
3. What Breaks: The security boundary fails due to the lack of proper restrictions on XSD string processing, allowing the attacker to access sensitive information.
4. Attacker's Prize: The attacker gains access to sensitive information, such as cloud provider credentials or internal network services, potentially leading to further lateral movement or data exfiltration.
Real-World Impact
An attacker can achieve significant impact by exploiting CVE-2026-15143. This can lead to sensitive information disclosure, such as cloud provider credentials or access to internal network services. If actively exploited in the wild, this vulnerability can result in severe consequences, including data theft, lateral movement, or ransomware deployment.
Detection & Defense
Immediate Mitigations
To mitigate CVE-2026-15143, it is recommended to upgrade to the latest version of guardrails-detectors and apply the necessary patches. Specifically, Red Hat OpenShift AI (RHOAI) users should upgrade to the patched versions of rhoai/odh-built-in-detector-rhel9 and rhoai/odh-guardrails-detector-huggingface-runtime-rhel9.
Detection Strategies
Defenders can detect exploitation attempts by monitoring log patterns, SIEM rules, and network signatures. Specifically, they can look for unusual server-side requests to arbitrary URLs or local file reads. MITRE ATT&CK techniques, such as T1190 (Exploit Public-Facing Application) and T1615 (Credentials in Files), may be applicable.
Long-Term Hardening
To prevent this class of vulnerability, it is essential to implement proper restrictions on XSD string processing and validate user input. Additionally, defenders should implement defense-in-depth strategies, such as network segmentation, access controls, and regular security audits.
Key Takeaways
* CVE-2026-15143 is a critical vulnerability in guardrails-detectors that allows remote attackers to supply arbitrary XSD strings.
* The vulnerability can lead to server-side requests to arbitrary URLs or local file reads, potentially resulting in sensitive information disclosure.
* Immediate mitigations include upgrading to the latest version of guardrails-detectors and applying necessary patches.
* Detection strategies involve monitoring log patterns, SIEM rules, and network signatures.
* Long-term hardening requires implementing proper restrictions on XSD string processing and validating user input.
Sources
* National Vulnerability Database (NVD) - CVE-2026-15143
* Red Hat Security Advisory - CVE-2026-15143