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Linux Kernel qede CVE-2026-74523

| EUVDEUVD-2026-59716 HIGH
2026-08-15 Linux GHSA-wf9x-rw9q-x6mf
7.5
CVSS 3.1 · Vendor: Linux
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Severity by source

Vendor (Linux) PRIMARY
7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
vuln.today AI
5.3 MEDIUM

Attack vector is adjacent (TX timeout potentially inducible by network flooding), but AC:H because VXLAN/GENEVE tunnel port configuration is a non-default prerequisite; no confidentiality or integrity impact.

3.1 AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
4.0 AV:A/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
SUSE
4.7 MEDIUM
AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Red Hat
5.5 MEDIUM
qualitative

Primary rating from Vendor (Linux).

CVSS VectorVendor: Linux

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Lifecycle Timeline

5
Analysis Generated
Aug 17, 2026 - 12:08 vuln.today
CVSS changed
Aug 17, 2026 - 06:22 NVD
7.5 (HIGH)
Patch available
Aug 15, 2026 - 13:04 EUVD
CVE Published
Aug 15, 2026 - 12:27 cve.org
HIGH 7.5
CVE Published
Aug 15, 2026 - 12:27 cve.org
UNKNOWN (no severity yet)

DescriptionCVE.org

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

qede: sync udp_tunnel ports outside qede_lock in the recovery path

A TX timeout on a qede NIC that has VXLAN/GENEVE tunnel ports configured wedges the rtnetlink control plane of the whole machine:

NETDEV WATCHDOG: ens6f1 (qede): transmit queue 2 timed out 10226 ms [qede_tx_timeout:586(ens6f1)]TX timeout on queue 2! [qede_recovery_handler:2665(ens6f0)]Starting a recovery process

The recovery path deadlocks on the driver's own mutex:

qede_sp_task rtnl_lock() mutex_lock(&edev->qede_lock) <- taken qede_recovery_handler qede_load udp_tunnel_nic_reset_ntf __udp_tunnel_nic_device_sync info->sync_table == qede_udp_tunnel_sync mutex_lock(&edev->qede_lock) <- same task: deadlock

The mutex is not recursive, so the kworker blocks on itself with rtnl_lock held, and neither lock is ever released. Every task that calls rtnl_lock() afterwards (ip, ovs-vswitchd, lldpad, IPv6 addrconf, sshd) blocks forever while the node still answers ping. In a vmcore from an affected production node rtnl_mutex.owner decodes to the very kworker blocked at the innermost mutex_lock() above.

Re-sync the tunnel ports from qede_sp_task() after the internal lock is dropped, still under rtnl_lock as the udp_tunnel API requires. This mirrors qede_open(), which calls udp_tunnel_nic_reset_ntf() under rtnl without the internal lock.

qede_recovery_handler() now returns whether it has successfully reloaded an open device, and the caller re-syncs the ports only in that case. This keeps the old gating exactly: a device that was down or a failed recovery returns false, as those paths never reached the udp_tunnel_nic_reset_ntf() call before either.

This was the only user of the qede_lock()/qede_unlock() helpers, so remove them.

AnalysisAI

Deadlock in the Linux kernel qede NIC driver's recovery path permanently wedges the rtnetlink control plane of any affected host when a TX timeout fires on a QLogic/Cavium FastLinQ interface with VXLAN or GENEVE tunnel ports configured. Systems in this state remain pingable but every subsequent caller of rtnl_lock - including ip, sshd, ovs-vswitchd, IPv6 addrconf, and lldpad - blocks indefinitely, denying all network management access until reboot. …

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access
TX timeout on qede NIC interface
Delivery
qede recovery handler acquires rtnl_lock then qede_lock
Exploit
udp_tunnel_nic_reset_ntf dispatches to qede_udp_tunnel_sync
Execution
qede_udp_tunnel_sync re-acquires qede_lock on same kworker
Persist
Kworker self-deadlocks with rtnl_lock held
Impact
Network control plane wedged indefinitely

Vulnerability AssessmentAI

Exploitation Three conditions must be simultaneously true: (1) the target host must run an unpatched Linux kernel from version 5.9 onward with the qede driver loaded, which requires QLogic/Cavium FastLinQ NIC hardware - a specialized enterprise/datacenter adapter; (2) at least one qede interface must have VXLAN or GENEVE UDP tunnel ports registered via the kernel udp_tunnel NIC infrastructure, a non-default configuration common in SDN/overlay deployments but absent in bare-metal environments without tunnel networking; (3) a TX timeout must occur on that interface, which can happen naturally under hardware stress or high load and may be inducible by a network-adjacent attacker flooding the NIC, but is not directly injectable by an unauthenticated remote attacker. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment The NVD-assigned CVSS vector AV:N/AC:L/PR:N/UI:N materially overstates exploitability: the vulnerability requires a qede NIC, VXLAN or GENEVE tunnel port configuration, and a TX timeout event - none of which an unauthenticated remote attacker can directly control. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario A datacenter host running a QLogic FastLinQ NIC in an OpenStack or OVN environment with VXLAN overlay networking experiences a TX timeout on a tunnel-bearing interface - either spontaneously under sustained high traffic load or induced by a remote actor flooding the NIC. The qede recovery handler fires from its kworker, acquires rtnl_lock and then qede_lock, and then attempts to re-acquire qede_lock via udp_tunnel_nic_reset_ntf(); the non-recursive mutex causes the kworker to block on itself with rtnl_lock permanently held, after which every operator tool that calls rtnl_lock (ip, sshd, ovs-vswitchd) blocks indefinitely, denying all network management access to the node.
Remediation Upgrade to a patched stable kernel: 6.6.151 or later on the 6.6.x series, 6.12.103 or later on 6.12.x, 6.18.44 or later on 6.18.x, 7.1.8 or later on 7.1.x, or 7.2-rc6 or later on the development branch. … Detailed patch versions, workarounds, and compensating controls in full report.

Recommended ActionAI

Within 24 hours, identify all production datacenter hosts with QLogic/Cavium FastLinQ network interfaces and VXLAN/GENEVE tunnel configurations using hardware inventory and network configuration audits. …

Sign in for detailed remediation steps and compensating controls.

Threat intelligence, references, and detailed analysis are available after sign-in.

Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 16.0 Affected

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CVE-2026-74523 vulnerability details – vuln.today

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