CVE-2026-89798: Linux Vulnerability

Description

In the Linux kernel, the following vulnerability has been resolved: rpcrdma: arm rn_done before publishing the notification rpcrdma_rn_register() inserts @rn into rd_xa with xa_alloc() before storing the caller's callback in rn->rn_done. The xarray makes @rn reachable to rpcrdma_remove_one(), which walks rd_xa and invokes rn->rn_done(rn) for every registered notification. A device removal that races a fresh registration can therefore observe @rn with rn_done still NULL, because the notification objects are zero allocated by their owners, and call through a NULL function pointer. Store rn->rn_done before xa_alloc() publishes @rn. The xarray's store-side and load-side ordering then guarantees that any CPU which finds @rn in rd_xa also observes the armed callback. rpcrdma_rn_unregister() treats a non-NULL rn_done as the sentinel for a completed registration, so the early store must not survive a failed registration. Clear rn_done again when xa_alloc() fails. Were it left set, the failed-accept cleanup path would call rpcrdma_rn_unregister() on an @rn that was never inserted, erasing an unrelated rd_xa slot and underflowing rd_kref.

Metrics

EPSS Probability

0.20%

9.9th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 7e86845a0346efc95fddaa97ce5cd6a8bda8c71c, < f9fe3cad43c42d874a388583552b39b411d886eb; >= 7e86845a0346efc95fddaa97ce5cd6a8bda8c71c, < 3c97b8e76ca2bba9e8770571413aed694068e78e; >= 7e86845a0346efc95fddaa97ce5cd6a8bda8c71c, < ea0408273ccf5df1fb52d9a1b9db4d31600dcb36; >= 7e86845a0346efc95fddaa97ce5cd6a8bda8c71c, < 5b06f706374c37375bdff9d21cc10e61df925a92
Linux	Linux	6.11

References

Timeline

Published: Sep 16, 2026
Last Modified: Sep 21, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-89798?

In the Linux kernel, the following vulnerability has been resolved: rpcrdma: arm rn_done before publishing the notification rpcrdma_rn_register() inserts @rn into rd_xa with xa_alloc() before storing the caller's callback in rn->rn_done. The xarray makes @rn reachable to rpcrdma_remove_one(), which walks rd_xa and invokes rn->rn_done(rn) for every registered notification. A device removal that races a fresh registration can therefore observe @rn with rn_done still NULL, because the notification objects are zero allocated by their owners, and call through a NULL function pointer. Store rn->rn_done before xa_alloc() publishes @rn. The xarray's store-side and load-side ordering then guarantees that any CPU which finds @rn in rd_xa also observes the armed callback. rpcrdma_rn_unregister() treats a non-NULL rn_done as the sentinel for a completed registration, so the early store must not survive a failed registration. Clear rn_done again when xa_alloc() fails. Were it left set, the failed-accept cleanup path would call rpcrdma_rn_unregister() on an @rn that was never inserted, erasing an unrelated rd_xa slot and underflowing rd_kref.

How severe is CVE-2026-89798?

Severity scoring for CVE-2026-89798 is pending analysis. The EPSS model estimates a 0.20% probability of exploitation in the next 30 days.

How do I fix CVE-2026-89798?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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