CVE-2026-89527 svcrdma: Use svc_xprt_put to free listener on create failure
A use-after-free vulnerability in the Linux kernel's svcrdma module allows attackers to cause a denial of service or potentially execute code via crafted network traffic.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-89527?
CVE-2026-89527 is an use after free vulnerability in Linux, published on 11 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
svcrdma: Use svc_xprt_put to free listener on create failure
svc_rdma_create() calls kfree(cma_xprt) when svc_rdma_create_listen_id() fails. svc_xprt_init() has already acquired a net namespace reference via get_net_track(); kfree bypasses svc_xprt_free() which releases it.
Replace the kfree() with svc_xprt_put() so the kref_init birth reference drops to zero and svc_xprt_free() dispatches svc_rdma_free() to clean up properly. sc_cm_id is still NULL at that point; the preceding patch added the necessary NULL guard in svc_rdma_free().
svc_xprt_free() also drops the module reference via module_put(), but the caller _svc_xprt_create() does the same on xpo_create failure, double-putting the single try_module_get() it acquired. Take a compensating __module_get() before the svc_xprt_put() to keep the count balanced, matching the convention in svc_rdma_accept()'s error path.
Which versions are affected by CVE-2026-89527?
How do I fix CVE-2026-89527?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-89527 being exploited?
There is no known exploitation of CVE-2026-89527 in the wild and no public exploit code.
Sources
Also known as AZL-100404, BELL-CVE-2026-89527, DEBIAN-CVE-2026-89527, GHSA-h2xv-x4xq-mhh8, UBUNTU-CVE-2026-89527.