Overview
CVE-2025-64750 describes a medium severity security vulnerability affecting SingularityCE and SingularityPRO, open-source container platforms. This vulnerability allows an attacker to potentially bypass Linux Security Module (LSM) restrictions under specific conditions. The vulnerability resides in how shared mounts are handled, allowing a malicious container to redirect LSM label write operations, effectively disabling LSM security controls.
Technical Details
This vulnerability arises when a user relies on LSM restrictions to prevent malicious operations within a SingularityCE or SingularityPRO container. An attacker can exploit this by crafting a malicious container image that redirects the mount of /proc to a destination that’s a shared mount. This shared mount can either be one pre-configured on the target system or one specified by the user during container execution. Critically, the attacker must also control the content of the shared mount point. This control can be achieved through another malicious container that binds to the same shared mount, or by compromising a user account with sufficient permissions on the host system to modify the shared mount’s contents.
The redirection allows the attacker to manipulate how LSM labels are applied, rendering them ineffective. This circumvents the intended security boundaries enforced by LSM, potentially allowing the malicious container to perform actions it would normally be prohibited from doing.
CVSS Analysis
The Common Vulnerability Scoring System (CVSS) assigns CVE-2025-64750 a score of 4.5 (Medium). This score reflects the specific conditions required for successful exploitation, notably the attacker’s need to control a shared mount and the reliance on user configurations to enable shared mounts.
Possible Impact
Successful exploitation of this vulnerability can lead to the following potential impacts:
- LSM Bypass: The primary impact is the circumvention of LSM security policies, allowing malicious containers to perform unauthorized actions.
- Privilege Escalation: In certain scenarios, bypassing LSM may lead to privilege escalation within the container, and potentially on the host system.
- Data Compromise: A compromised container could potentially access and exfiltrate sensitive data from the host system or other containers.
- System Instability: Malicious actions performed by a compromised container could destabilize the host system.
Mitigation and Patch Steps
The vulnerability is fixed in the following versions:
- SingularityCE 4.3.5 and later
- SingularityPRO 4.1.11 and later
- SingularityPRO 4.3.5 and later
Immediate Action: Users of SingularityCE and SingularityPRO are strongly advised to upgrade to the patched versions as soon as possible.
Workarounds: While upgrading is the best solution, consider these temporary mitigations:
- Carefully Review Container Images: Scrutinize container images for suspicious mount points or unusual configurations.
- Restrict Shared Mounts: Minimize the use of shared mounts and carefully control access to existing shared mount points.
- Monitor Container Activity: Implement monitoring solutions to detect anomalous container behavior that might indicate an attempted exploit.
