CVE-2026-98561
Received Received - Intake

Use-After-Free in Linux Kernel XArray Lock Handling

Publication date: 2026-10-18

Last updated on: 2026-10-18

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: nfp: hold IPsec RX state under the XArray lock nfp_net_ipsec_rx() drops the XArray lock before taking a reference to the xfrm_state it found. The delete path can erase the entry and drop the last state reference in that interval. RX can then try to increment a zero refcount after the state has been queued for destruction. The driver queues firmware invalidation asynchronously; the delete path does not wait for the command to complete or drain pending RX processing. The XFRM garbage collector waits for an RCU grace period before freeing the state. That delays reclamation but does not make acquiring a reference from zero valid. Take the xfrm_state reference before releasing the XArray lock so xa_erase() cannot run between lookup and reference acquisition.

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Meta Information

Published
2026-10-18
Last Modified
2026-10-18
Generated
2026-10-18
AI Q&A
2026-10-18
EPSS Evaluated
N/A
NVD
CVE-2026-98561
EUVD
EUVD-2026-103606

Affected Vendors & Products

Showing 6 associated CPEs
Vendor Product Version / Range
Linux Linux 57f273adbcd44172cbe0bd10b8b7408dd255699f
Linux Linux 57f273adbcd44172cbe0bd10b8b7408dd255699f
Linux Linux 57f273adbcd44172cbe0bd10b8b7408dd255699f
Linux Linux 57f273adbcd44172cbe0bd10b8b7408dd255699f
Linux Linux 57f273adbcd44172cbe0bd10b8b7408dd255699f
Linux Linux 6.2

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a race condition in the nfp driver's IPsec RX path. The issue occurs when the driver drops the XArray lock before taking a reference to an xfrm_state object, allowing the delete path to erase the entry and drop the last state reference. This can lead to a use-after-free scenario where RX processing attempts to increment a zero refcount after the state has been queued for destruction.

Detection Guidance

This vulnerability is specific to the Linux kernel's nfp driver and IPsec RX state handling. Detection requires checking kernel logs for IPsec-related errors or crashes, particularly involving the nfp driver and XArray lock operations. Examine logs for messages about refcount overflows or state destruction issues.

Impact Analysis

This vulnerability could cause system instability, crashes, or potential privilege escalation if exploited. Systems using the affected Linux kernel with the nfp driver and IPsec functionality enabled are at risk. Attackers might trigger the race condition to corrupt kernel memory, leading to denial-of-service or unauthorized access.

Mitigation Strategies

Apply the latest Linux kernel update that includes the fix for this vulnerability. If immediate patching is not possible, disable IPsec RX processing in the nfp driver or restrict network traffic using IPsec until the update is applied.

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