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Fencer Vulns
high 8.1

CVE-2026-93224 json

svcrdma: Fix unmatched rn_unregister on failed accept

published 2026-09-24 46 d ago modified 2026-10-19 21 d ago also EUVD-2026-86227

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 39%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

svcrdma: Fix unmatched rn_unregister on failed accept

When svc_rdma_accept() takes the errout path before rpcrdma_rn_register() has succeeded, the existing cleanup block calls rpcrdma_rn_unregister(dev, &newxprt->sc_rn) unconditionally. svcxprt_rdma is kzalloc'd, so on that path sc_rn.rn_index is 0 and sc_rn.rn_done is NULL; the unregister therefore xa_erase()s another caller's slot 0 and performs an unmatched kref_put() on the rpcrdma_device's rd_kref.

The same errout also brackets the cleanup with svc_xprt_get()/ svc_xprt_put() around the kref_init() birth reference. The kref goes 1 -> 2 -> 1 and never reaches 0, so the svcxprt_rdma (and the net/ns_tracker it pinned) is leaked on every failed accept.

rpcrdma_rn_register() writes rn->rn_done last, only after xa_alloc() and kref_get() have both succeeded, so rn_done == NULL is a natural "never registered" sentinel. Guard rpcrdma_rn_unregister() with an early return when rn_done is NULL, and clear rn_done before the matching xa_erase() so a repeated unregister is also a no-op.

With that guard in place, the accept errout drops the kref_init() birth reference via svc_xprt_put(), which dispatches svc_rdma_free(). Teardown of sc_qp, sc_sq_cq, sc_rq_cq, and sc_pd runs under existing IS_ERR/NULL guards in svc_rdma_free(); sc_rn is covered by the new rn_done sentinel; sc_cm_id is non-NULL on every errout path because svc_rdma_accept() dereferences it above the first goto errout.

svc_xprt_free() drops the module reference associated with the freed transport, and svc_handle_xprt() drops its pre-acquired reference when ->xpo_accept() returns NULL. Take a replacement module reference before svc_xprt_put() so the two module_put()s remain balanced.

The rn_done guard also covers svc_rdma_free()'s non-listener call to rpcrdma_rn_unregister() for transports whose register attempt failed or never ran.

Patch / fix

  • Linux Linux 6.12.109, 6.16, 6.18.50, 7.2.4, 7.3
  • linux Debian 13 6.12.111-1
  • linux Debian 14 7.2.6-1
  • linux-6.12 Debian 12 6.12.111-1~deb12u1

debian advisories DEBIAN-CVE-2026-93224

  • linux Ubuntu 26.04 LTS 7.0.0-42.42
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
  • linux-ibm Ubuntu 26.04 LTS 7.0.0-1017.17
  • linux-riscv Ubuntu 26.04 LTS 7.0.0-42.42.1
  • linux-oracle Ubuntu 26.04 LTS 7.0.0-1015.16
  • linux-hwe-7.0 Ubuntu 24.04 LTS 7.0.0-42.42~24.04.1
  • linux-oem-7.0 Ubuntu 26.04 LTS 7.0.0-1017.17

ubuntu advisories UBUNTU-CVE-2026-93224

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-source openSUSE Tumbleweed 7.2.8-1.1

opensuse advisories openSUSE-SU-2026:11893-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-93224 updated cvss 8.1

kernel: svcrdma: Fix unmatched rn_unregister on failed accept

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 10 kernel
    affected: workaround, no fix available
  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.