CVE-2026-47215 in Singularity
Summary
by MITRE • 09/15/2026
SingularityCE and SingularityPRO are open source container platforms. Prior to SingularityCE 4.4.2 and SingularityPRO 4.3.9 and 4.1.14, incorrect path-string matching in the singularity.conf limit container paths directive allows a container in a sibling directory such as /data/safe-but-unsafe to be run when /data/safe is allowed under setuid mode. This permits a user to run a container from outside the administrator's configured path allowlist. Installations that do not use limit container paths are not affected. This issue is fixed in SingularityCE 4.4.2 and SingularityPRO 4.3.9 and 4.1.14.
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Analysis
by VulDB Data Team • 09/15/2026
The vulnerability identified involves a critical flaw in the path-string matching logic within the singularity.conf configuration file of SingularityCE and SingularityPRO container platforms. Specifically, the directive designed to limit which directories containers can be executed from fails to enforce strict prefix validation when operating under setuid mode. This implementation error allows for an incorrect interpretation of directory boundaries, where a parent directory path is considered sufficient authorization to execute images located in sibling or subdirectories that were not explicitly permitted by the system administrator. For instance, if the configuration restricts container execution to paths starting with /data/safe, the flawed logic erroneously permits containers stored in directories such as /data/safe-but-unsafe because they share a common prefix string rather than being strictly contained within the designated safe directory structure.
This technical flaw results in a significant bypass of access control mechanisms intended by the system administrator to isolate container workloads and restrict execution privileges. By allowing users to launch containers from outside the configured allowlist, an attacker or malicious insider can potentially execute untrusted code with elevated privileges granted through setuid binaries. This undermines the security boundary established for multi-tenant environments where strict isolation is required. The operational impact includes unauthorized access to system resources, potential privilege escalation if the container runtime allows further exploitation, and a violation of compliance requirements that mandate strict control over executable paths in sensitive infrastructure deployments.
The vulnerability aligns with CWE-284 Improper Access Control, as it represents a failure to properly restrict access to specific resource directories based on configured policies. Furthermore, from an adversary perspective, this flaw facilitates lateral movement or privilege escalation within the host system by allowing execution of arbitrary container images that bypass administrative restrictions. In terms of MITRE ATT&CK mapping, this relates to techniques involving abuse of configuration settings and potential exploitation for initial access or defense evasion depending on how the misconfigured paths are leveraged in a broader attack chain.
To mitigate this risk, organizations running SingularityCE prior to version 4.4.2 or SingularityPRO prior to versions 4.3.9 and 4.1.14 must upgrade immediately to the patched releases where the path-string matching logic has been corrected to enforce strict directory containment rather than loose prefix matching. For installations that do not utilize the limit container paths directive, this specific vulnerability does not apply; however, maintaining up-to-date software remains a fundamental security best practice. Administrators should also audit their singularity.conf files to ensure no other misconfigurations exist and verify that setuid binaries are deployed only on systems where such privileges are strictly necessary and monitored.