Overview
CVE-2025-13193 is a medium-severity vulnerability found in libvirt, a virtualization management library. This flaw allows unprivileged users to potentially access sensitive information from guest operating systems. The vulnerability stems from the incorrect creation of external inactive snapshots for shut-down virtual machines as world-readable. This unintended exposure enables unauthorized users to inspect the contents of the guest OS images.
Technical Details
The issue arises when libvirt creates external snapshots of VMs that are already shut down. Instead of restricting permissions appropriately, these snapshots are inadvertently created with world-readable permissions. This means that any user on the system with access to the snapshot file can potentially read its contents, bypassing intended access controls of the virtual machine and hypervisor.
This vulnerability impacts configurations where external snapshots are used as part of backup, recovery, or testing procedures.
CVSS Analysis
The Common Vulnerability Scoring System (CVSS) assigns CVE-2025-13193 a score of 5.5. This signifies a MEDIUM severity vulnerability. The CVSS vector is likely AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N, indicating:
- Attack Vector (AV): Local (L) – An attacker must have local access to the system.
- Attack Complexity (AC): Low (L) – The attack is relatively easy to execute.
- Privileges Required (PR): Low (L) – An attacker requires low privileges to exploit the vulnerability.
- User Interaction (UI): None (N) – No user interaction is required.
- Scope (S): Unchanged (U) – The vulnerability’s impact is limited to the vulnerable component.
- Confidentiality (C): High (H) – There is a high impact on confidentiality. Sensitive information is disclosed.
- Integrity (I): None (N) – There is no impact on integrity.
- Availability (A): None (N) – There is no impact on availability.
Possible Impact
The exploitation of CVE-2025-13193 can lead to significant information disclosure. An unprivileged user could potentially:
- Read sensitive data stored within the guest operating system, such as passwords, cryptographic keys, or confidential documents.
- Gain insights into the guest OS configuration and running applications, which could be used for further attacks.
- Circumvent security controls designed to isolate virtual machines.
Mitigation and Patch Steps
To mitigate the risk posed by CVE-2025-13193, it is crucial to apply the necessary patches provided by your Linux distribution or virtualization platform vendor. Follow these steps:
- Update Libvirt: Update to the latest version of libvirt that addresses the vulnerability. Check your distribution’s security advisories for specific instructions.
- Review Existing Snapshots: Review the permissions of any existing external snapshots to ensure they are not world-readable. If necessary, adjust the permissions to restrict access to authorized users only. A common fix would be to use `chmod 600
` to restrict access to the owner. - Monitor Snapshot Creation: Implement monitoring to detect the creation of world-readable snapshots and alert administrators.
