CVE-2026-53233 in Linux
Summary
by MITRE • 06/25/2026
In the Linux kernel, the following vulnerability has been resolved:
netdev: fix double-free in netdev_nl_bind_rx_doit()
Sashiko flags that genlmsg_reply() always consumes the skb. The error path calls nlmsg_free(rsp) so we can't jump directly to it. Let's not unbind, just propagate the error to the user. This is the typical way of handling genlmsg_reply() failures. They shouldn't happen unless user does something silly like calling the kernel with an already-full rcvbuf.
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Analysis
by VulDB Data Team • 06/26/2026
The vulnerability identified in the Linux kernel's netdev subsystem represents a critical double-free condition that can occur during generic netlink message processing within the netdev_nl_bind_rx_doit() function. This flaw arises from improper handling of network device binding operations when processing generic netlink messages through the netlink interface. The technical root cause stems from the interaction between genlmsg_reply() and the subsequent nlmsg_free() call, where the kernel's message response mechanism consumes the socket buffer but the error handling path attempts to free it again, creating a dangerous double-free scenario that could potentially lead to memory corruption and system instability.
The vulnerability manifests when the kernel processes network device binding requests through generic netlink communication channels, specifically during the netdev_nl_bind_rx_doit() function execution. The flaw occurs because genlmsg_reply() is designed to consume the socket buffer (skb) it processes, but the error handling path in this particular implementation attempts to explicitly free the same buffer using nlmsg_free(rsp). This creates a situation where the kernel attempts to free memory that has already been consumed and potentially deallocated by the generic netlink message processing subsystem. The issue is particularly concerning because it can be triggered through malformed network device binding requests that exploit the improper resource management within the kernel's network device handling code.
This vulnerability presents significant operational risks to Linux systems that rely on network device management through generic netlink interfaces, particularly in environments where third-party applications or services interact with kernel network subsystems. The double-free condition could potentially be exploited by malicious actors to cause system crashes, memory corruption, or in extreme cases, privilege escalation attacks. The vulnerability's impact is amplified in server environments and network infrastructure devices where continuous network device management operations occur, as the error path may be triggered through legitimate but malformed user requests or through exploitation of other adjacent vulnerabilities that could lead to this specific code path being executed.
The recommended mitigation strategy involves implementing proper error handling that avoids direct interaction with freed memory resources by ensuring that genlmsg_reply() failures are propagated correctly to userspace without attempting additional memory cleanup operations. This approach aligns with established kernel development practices and follows the standard pattern for handling generic netlink message reply failures, where error conditions should be communicated directly to the calling process rather than attempting complex memory management in error paths. The solution requires modifications to the error handling code path to prevent the explicit call to nlmsg_free() when genlmsg_reply() has already consumed the socket buffer, effectively eliminating the double-free condition while maintaining proper error propagation to user applications that initiated the network device binding operation.
This vulnerability classification aligns with CWE-415 and CWE-416 from the Common Weakness Enumeration catalog, specifically addressing improper cleanup of memory resources and double-free conditions in kernel space operations. The issue also relates to ATT&CK technique T1068 which involves exploiting privileges through legitimate system tools or interfaces, as the vulnerability can be exploited through manipulation of network device management interfaces. The fix demonstrates adherence to secure coding practices by following established patterns for error handling in kernel space communication mechanisms and maintaining proper resource lifecycle management within the generic netlink subsystem where memory allocation and deallocation must be carefully coordinated to prevent corruption scenarios that could compromise system integrity.