UBUNTU-CVE-2026-98617: Low severity ubuntu/linux-hwe-edge vulnerability
In the Linux kernel, the following vulnerability has been resolved: eth: fbnic: use the Rx queue napi pointer to find the napi vector The queue management ndos pick the napi vector for an Rx queue with: nv = fbn->napi[idx % fbn->numnapi]; The issue is this is only correct in the cases where there are no standalone Tx vectors. In those cases we were allocating the Tx vectors first and then the Rx so the queues would be pointing to Tx NAPI vectors instead of the Rx ones. The mapping the ndos want is already recorded. fbnicsetnetifnapi() publishes it with netifqueuesetnapi(), which stores the napi pointer in netdevrxqueue.napi, and fbnicresetnetifnapi() clears it again. Both run under the netdev instance lock that the queue management ndos also hold, so the pointer can be read directly. Use it and drop the divide. The pointer is NULL exactly while the datapath is down, so fbnicqueuememalloc() can reject that case rather than reaching into freed state: netdevrxqueuerestart() calls it before it tests netifrunning(), and fbnicpmsuspend() leaves netifrunning() true across a PCIe recovery that never completes, so a queue restart can arrive after fbnicstop() has freed the rings and the vectors. fbnicstop() clears the association in fbnicresetnetifqueues() before fbnicfreenapivectors(), so the NULL is always published first. fbnicqueuestart() and fbnicqueuestop() need no check of their own, as netdevrxqueuereconfig() only reaches them once fbnicqueuememalloc() has succeeded under the same instance lock.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
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ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42~24.04.1 - Upgrade
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ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1~24.04.1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-42.42 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1016.17 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1016.18 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1015.16 - Upgrade
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ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1
Event History
Frequently Asked Questions
Which systems are exposed to this issue?
Systems using the Linux kernel fbnic Ethernet driver are relevant. The faulty queue-to-NAPI-vector selection occurs when standalone transmit NAPI vectors are present; configurations without standalone transmit vectors use the prior mapping correctly.
What conditions can trigger the vulnerable path?
A receive-queue restart must reach queue memory allocation while the datapath is down. The description identifies a possible trigger after fbnic_stop() has freed state, including a PCIe recovery that does not complete while netif_running() remains true.
How does the fix prevent the problem?
The fix reads the NAPI pointer already associated with the receive queue instead of deriving a vector index from the queue index. It also rejects queue memory allocation when that pointer is NULL, which denotes that the datapath is down.