CVE-2025-24965 in crun
Summary
by MITRE • 02/19/2025
crun is an open source OCI Container Runtime fully written in C. In affected versions A malicious container image could trick the krun handler into escaping the root filesystem, allowing file creation or modification on the host. No special permissions are needed, only the ability for the current user to write to the target file. The problem is fixed in crun 1.20 and all users are advised to upgrade. There are no known workarounds for this vulnerability.
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Analysis
by VulDB Data Team • 02/27/2025
The vulnerability identified as CVE-2025-24965 affects crun, an open source OCI container runtime implemented in C, which serves as a critical component in containerized environments where container images are executed. This flaw resides within the krun handler implementation and represents a significant security regression that undermines the fundamental isolation principles that containerization technologies are designed to enforce. The vulnerability allows for privilege escalation through a container escape mechanism that bypasses the expected filesystem boundaries between containerized processes and the host operating system. The flaw specifically manifests when processing malicious container images that exploit improper handling of filesystem operations within the krun handler context, enabling unauthorized access to host filesystem resources.
The technical implementation of this vulnerability stems from inadequate validation and boundary checking within the container runtime's filesystem handling routines. When a malicious container image is executed, the krun handler fails to properly enforce the root filesystem restrictions that should isolate the container's filesystem from the host system. This allows the containerized process to traverse beyond its designated boundaries and gain access to the host's filesystem, where it can create or modify files without requiring elevated privileges. The vulnerability operates at the kernel level through the container runtime's interaction with the host's filesystem layer, making it particularly dangerous as it exploits the trust relationship between the container runtime and the host operating system. The flaw is classified as a container escape vulnerability and aligns with CWE-276, which addresses improper privileges and access control issues in software systems. The vulnerability's impact is amplified by the fact that it requires no special permissions beyond standard user access to the target file system, making it accessible to any user with basic file system write capabilities.
The operational impact of CVE-2025-24965 extends beyond simple privilege escalation, as it fundamentally compromises the security model that containerization relies upon for isolation. An attacker who can execute container images within an environment running vulnerable crun versions can potentially access sensitive host files, modify critical system components, or establish persistence mechanisms on the host system. This vulnerability undermines the security assumptions of container orchestration platforms and cloud environments where crun is commonly deployed, potentially leading to complete host compromise. The attack vector is particularly concerning because it can be exploited through standard container image execution processes without requiring additional privileges or specialized attack tools. The vulnerability's exploitation does not require elevated system permissions, which means it can be leveraged by malicious actors with minimal privileges, making it a significant concern for multi-tenant environments and cloud infrastructure providers.
Organizations utilizing crun as their container runtime must immediately implement remediation measures to address this vulnerability, as there are no viable workarounds available. The fix for this issue is incorporated in crun version 1.20, which includes enhanced filesystem boundary checking and improved validation of container image contents before execution. Security teams should conduct comprehensive vulnerability assessments across all systems running affected crun versions to identify potential exploitation attempts. The vulnerability's presence in widely deployed container runtimes makes it a high-priority concern for security operations teams, requiring immediate attention in security update schedules. Organizations should implement monitoring for unauthorized filesystem modifications and container escape attempts, particularly in environments where untrusted container images are executed. The remediation process should include not only upgrading to crun 1.20 but also verifying that the upgrade has been successfully applied across all container orchestration platforms and deployment environments. This vulnerability represents a critical failure in the container security model and highlights the importance of thorough security testing for container runtime implementations, particularly those written in systems programming languages where memory safety issues can lead to severe security implications. The flaw demonstrates the necessity of implementing proper input validation and boundary checking mechanisms in security-critical components that operate at the interface between user-space applications and system-level resources.