Actively exploited vulnerability
Linux Kernel: vulnerability flaw under attack
CVE-2023-0386 · Linux Kernel Improper Ownership Management Vulnerability
What is affected
Linux Kernel is found on ordinary personal computers and phones, so this is not only a problem for companies. If you use it and have not updated since the fix was released, you are exposed.
Linux Kernel contains an improper ownership management vulnerability, where unauthorized access to the execution of the setuid file with capabilities was found in the Linux kernel’s OverlayFS subsystem in how a user copies a capable file from a nosuid mount into another mount. This uid mapping bug allows a local user to escalate their privileges on the system.
What an attacker can do
This is a vulnerability flaw. It lets an attacker misuse the product in a way its maker did not intend. CISA lists it because attackers are confirmed to be using it against real systems.
- How it is reached
- Needs access to the device or a file opened on it
- Access the attacker needs
- A basic user account
- Does the victim have to do something?
- No, works without the victim doing anything
What to do
- Update Linux Kernel now. Open the update or "About" screen, install whatever is offered and restart the app or device, because the fix is not active until you do.
- Turn on automatic updates so the next fix arrives without you having to look for it.
- If your device is too old to receive this update, stop using the affected app for anything sensitive and plan a replacement.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Vendor advisories and fixes
- git.kernel.orggit.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=4f11ada10d0a
- access.redhat.comaccess.redhat.com/security/cve/cve-2023-0386
- security.netapp.comsecurity.netapp.com/advisory/ntap-20230420-0004/
How urgent is it
CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on June 17, 2025, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by July 8, 2025, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.
The EPSS model estimates a 7.9% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 95% of all scored vulnerabilities.
Its CVSS severity score is 7.8 out of 10 (high), as recorded in the US National Vulnerability Database.
Technical description
A flaw was found in the Linux kernel, where unauthorized access to the execution of the setuid file with capabilities was found in the Linux kernel’s OverlayFS subsystem in how a user copies a capable file from a nosuid mount into another mount. This uid mapping bug allows a local user to escalate their privileges on the system.