Bug 2546437 (CVE-2026-98257)

Summary: CVE-2026-98257 kernel: rds: ib: use rds_conn_drop() on protocol version mismatch
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's Reliable Datagram Sockets (RDS) subsystem. A remote attacker can trigger a Denial of Service (DoS) by negotiating an incompatible protocol version during connection establishment. This mismatch causes the kernel to attempt a synchronous connection teardown while retaining an internal lock, resulting in a deadlock. Consequently, connection workqueues stall permanently, disrupting network communication.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2026-10-06 09:20:41 UTC 
In the Linux kernel, the following vulnerability has been resolved:

rds: ib: use rds_conn_drop() on protocol version mismatch

rds_ib_cm_connect_complete() runs from the RDMA-CM event handler with
conn->c_cm_lock held.  When the peer negotiates a protocol version
older than RDS_PROTOCOL_COMPAT_VERSION, the handler calls
rds_conn_destroy(), which is only safe in the rmmod path: it
synchronously tears the connection down and flush_work()es the
shutdown work cp_down_w.

That shutdown work (rds_conn_shutdown()) needs cp_cm_lock, which is
the very lock the event handler still holds, so the flush never
completes: the two workers wait on each other and the RDS connection
workqueues stall for good.

All other RDMA-CM failure paths (REJECTED, CONNECT_ERROR,
DISCONNECTED) use rds_conn_drop(), which marks the connection
RDS_CONN_ERROR and schedules the shutdown work asynchronously.  Use
it here as well.
Comment 1 gkamathe 2026-10-10 18:14:48 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98257.mbox