UBUNTU-CVE-2026-72342: High severity ubuntu/linux-hwe-edge vulnerability
In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix HV VHCA stats agent registration race mlx5ehvvhcastatscreate() registers the stats agent through mlx5hvvhcaagentcreate(). The helper publishes the agent in hvvhca->agents[type] under agentslock and immediately schedules an asynchronous control invalidation on the HV VHCA workqueue before returning to mlx5e. The asynchronous invalidation invokes the control agent's invalidate callback, which reads the hypervisor control block and forwards the command to mlx5ehvvhcastatscontrol(). That callback may either: - call canceldelayedworksync(&priv->statsagent.work), or - call queuedelayedwork(priv->wq, &sagent->work, sagent->delay). However, the delayedwork and priv->statsagent.agent are only initialized after mlx5hvvhcaagentcreate() returns to mlx5e: agent = mlx5hvvhcaagentcreate(...); / publish + invalidate / ... priv->statsagent.agent = agent; / too late / INITDELAYEDWORK(&priv->statsagent.work, ...); / too late / If the asynchronous control path runs before the two assignments above, it can: - Operate on an uninitialized delayedwork whose timer.function is NULL. queuedelayedwork() calls addtimer() unconditionally, so when the timer expires the timer softirq invokes a NULL function pointer. - Re-initialize the timer later through INITDELAYEDWORK() while the timer is already enqueued in the timer wheel, corrupting the hlist (entry.pprev cleared while the previous bucket node still points at this entry). - When the worker eventually runs, mlx5ehvvhcastatswork() reads sagent->agent (NULL) and dereferences it inside mlx5hvvhcaagentwrite(). Fix this by: - Initializing priv->statsagent.work before invoking mlx5hvvhcaagentcreate(), so the work is always in a valid state when the control callback observes it. - Adding a struct mlx5hvvhcaagent ctxupdate out-parameter to mlx5hvvhcaagentcreate(). The helper writes the agent pointer to ctxupdate before publishing into hvvhca->agents[] and triggering the agentsupdate flow, so any callback subsequently invoked from that flow already sees a valid priv->statsagent.agent. This avoids having the control callback participate in agent initialization. While at it, access priv->statsagent.agent with READONCE()/WRITEONCE() for the cross-CPU access with the worker, and clear priv->statsagent.buf on the agentcreate() failure path.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 6.8.0-147.147 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 6.8.0-1067.70 - Upgrade
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ubuntu/linux-aws-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1014.14~24.04.1 - Upgrade
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ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 6.8.0-1071.79 - Upgrade
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ubuntu/linux-azure-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17~24.04.1 - Upgrade
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ubuntu/linux-azure-fdeto a version that resolves this vulnerability.Fixed in 6.8.0-1069.76 - Upgrade
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ubuntu/linux-azure-fde-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1016.16~24.04.1 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 6.8.0-1071.79 - Upgrade
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ubuntu/linux-gcp-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1014.14~24.04.1 - Upgrade
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ubuntu/linux-gketo a version that resolves this vulnerability.Fixed in 6.8.0-1066.74 - Upgrade
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ubuntu/linux-gkeopto a version that resolves this vulnerability.Fixed in 6.8.0-1052.56 - Upgrade
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ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-38.38~24.04.4 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 6.8.0-1067.68 - Upgrade
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ubuntu/linux-lowlatencyto a version that resolves this vulnerability.Fixed in 6.8.0-147.147.1 - Upgrade
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ubuntu/linux-nvidia-tegrato a version that resolves this vulnerability.Fixed in 6.8.0-1036.39 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 6.8.0-1064.67 - Upgrade
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ubuntu/linux-oracle-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1013.13~24.04.1 - Upgrade
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ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-38.38.1~24.04.1 - Upgrade
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ubuntu/linux-bluefieldto a version that resolves this vulnerability.Fixed in 6.8.0-1033.38 - Upgrade
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ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 6.8.1-1062.63 - Upgrade
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ubuntu/linux-aws-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1067.70+fips1 - Upgrade
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ubuntu/linux-azure-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1071.79+fips1 - Upgrade
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ubuntu/linux-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-147.147+fips1 - Upgrade
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ubuntu/linux-gcp-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1071.79+fips1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-38.38 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1014.14 - Upgrade
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ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-azure-fdeto a version that resolves this vulnerability.Fixed in 7.0.0-1016.16 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1014.14 - Upgrade
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ubuntu/linux-gketo a version that resolves this vulnerability.Fixed in 7.0.0-1008.9 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1015.15 - Upgrade
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ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1015.15 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1013.13 - Upgrade
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ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 7.0.0-38.38.1 - Upgrade
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ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-38.38.1 - Compensating control
Add a ctx_update out-parameter to mlx5_hv_vhca_agent_create(), write the agent pointer to *ctx_update before publishing it in hv_vhca->agents[] and triggering the agents_update flow, and initialize priv->stats_agent.work before invoking mlx5_hv_vhca_agent_create().
- Compensating control
Access priv->stats_agent.agent with READ_ONCE() and WRITE_ONCE() for cross-CPU access between the control path and the worker.
- Operational
Clear priv->stats_agent.buf on the mlx5_hv_vhca_agent_create() failure path.
Event History
Frequently Asked Questions
Which Ubuntu kernel packages are in scope?
The affected software list includes ubuntu/linux, ubuntu/linux-azure, ubuntu/linux-gcp, ubuntu/linux-aws-fips, ubuntu/linux-azure-fips, ubuntu/linux-fips, ubuntu/linux-gcp-fips, and ubuntu/linux-realtime. No affected or fixed package versions are provided.
What access does an attacker need according to the supplied severity vector?
The vector identifies the attack vector as local, with low attack complexity, no required privileges, and no user interaction. The supplied data does not describe the specific local trigger or required hardware environment.
What can happen if the race is reached?
The asynchronous control path can run before the statistics agent pointer and delayed work item are initialized. It may then cancel or queue uninitialized delayed work whose timer function is NULL.