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The vulnerability CVE-2025-37998 exists within the `output_userspace()` function of the Open vSwitch (OVS) kernel module. The flaw stems from the function’s unsafe parsing of Netlink message attributes. Netlink is a communication interface used for transferring information between kernel and user-space processes. The vulnerable code used manual, unchecked iteration over these nested attributes. This improper parsing fails to validate the length and structure of each attribute adequately. An attacker can craft a malicious Netlink packet with malformed or improperly nested attributes. When this packet is processed, the kernel’s attribute parser can read or write memory outside the bounds of the intended buffer. This occurs because the manual iteration logic does not respect the proper length boundaries defined in the packet header. The consequence is an out-of-bounds memory access within the kernel space. This type of corruption can lead to a kernel crash (Denial of Service) or, in more sophisticated attacks, potential privilege escalation. The kernel may become unstable or allow the execution of arbitrary code with elevated privileges. The issue was resolved by replacing the unsafe manual iteration with the secure `nla_for_each_nested()` macro. This helper function automatically ensures that only well-formed attributes within the correct boundaries are processed, eliminating the out-of-bounds access.
Platform: Linux Kernel (openvswitch)
Version: Affected versions
Vulnerability: Out-of-bounds read/write
Severity: High
date: 2025-05-29
Prediction: Patch expected 2025-06-12
What Undercode Say:
`uname -r`
`lsmod | grep openvswitch`
`dmesg | tail -20`
`cat /proc/net/ovs/`
How Exploit:
Attackers craft and send a malicious Netlink packet containing nested attributes with incorrect lengths to a system with the Open vSwitch kernel module loaded. This triggers the improper memory access in the kernel during packet processing.
Protection from this CVE
Apply kernel patch.
Update system packages.
Disable unneeded modules.
Impact:
Kernel memory corruption.
Denial of Service.
Potential privilege escalation.
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Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
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