CVE-2026-98630 in Linux
Summary
by MITRE • 10/18/2026
In the Linux kernel, the following vulnerability has been resolved:
eth: fbnic: Fix payload page pool error cleanup
The payload page pool pointer contains an error pointer when its allocation fails. The cleanup path passes that error pointer to page_pool_destroy() instead of destroying the header page pool. This can dereference the error pointer and leave the header page pool allocated.
Destroy the header page pool instead.
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Analysis
by VulDB Data Team • 10/18/2026
The Linux kernel networking subsystem, specifically within the fbnic driver for Broadcom Ethernet controllers, contains a critical resource management flaw in its payload page pool initialization sequence. The vulnerability arises during the allocation phase where the system attempts to establish memory pools required for packet processing. When the allocation of the payload page pool fails, the kernel correctly sets the pointer to an error value rather than null or valid memory. However, the subsequent cleanup path exhibits a logical inversion in its destruction routine. Instead of targeting the header page pool which was successfully allocated prior to the failed payload allocation, the code erroneously passes the invalid error pointer associated with the payload pool directly into the page_pool_destroy function.
This implementation defect leads to two distinct operational consequences that compromise system stability and resource integrity. First, passing an error pointer to a destruction routine typically results in undefined behavior because such pointers are not valid memory addresses but rather encoded error codes. This can trigger a kernel panic or general protection fault due to invalid dereference attempts during the cleanup process. Second, even if the crash is avoided through specific compiler optimizations or architectural behaviors that mask immediate crashes, the logic failure ensures that the header page pool remains allocated in system memory without being released. This constitutes a resource leak where kernel memory is consumed but never returned to the available pool for future use.
From an industry standards perspective, this vulnerability aligns with CWE-401 which describes missing release of memory after effective usage. The failure to properly deallocate resources during error handling paths is a classic example of improper cleanup logic that leads to resource exhaustion over time if triggered repeatedly in high-throughput network environments. Additionally, the potential for triggering kernel crashes via invalid pointer dereference relates to CWE-476 which covers NULL pointer dereferences and similar invalid memory access patterns often exploited or encountered during fault conditions. The ATT&CK framework does not directly map this specific internal logic error as a tactic since it is an unintentional flaw rather than an adversary technique, but the resulting instability could be leveraged in denial-of-service scenarios if an attacker can induce repeated allocation failures under load.
The operational impact of this vulnerability includes potential system crashes leading to service disruption and gradual memory degradation due to leaked kernel structures. In production environments handling significant network traffic, frequent triggering of this error path during transient resource pressure events could lead to cumulative memory leaks that eventually exhaust available kernel memory pools. This may cause broader subsystem failures beyond just the fbnic driver affecting overall host stability. The fix involves correcting the cleanup logic to ensure that when payload allocation fails, the previously allocated header page pool is correctly identified and destroyed using the appropriate API call rather than attempting to destroy the failed payload pointer.
Mitigation strategies primarily involve applying the upstream kernel patch provided by Linux maintainers which corrects the conditional branch in the error handling path. Administrators should prioritize updating their systems with patched versions of the fbnic driver or the broader kernel release containing this fix. For environments where immediate patching is not feasible, monitoring for signs of memory pressure and reviewing dmesg logs for allocation failures can help identify affected instances before they lead to critical system instability. Long-term architectural improvements should include more robust error handling patterns that validate pointer states before performing resource deallocation operations to prevent similar logic errors in future driver developments.