UBUNTU-CVE-2026-72343: High severity ubuntu/linux-hwe-edge vulnerability
In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix HV VHCA stats zero-sized buffer allocation mlx5ehvvhcastatscreate() is called from mlx5enicenable(), before mlx5eopen(). At that point priv->statsnch is still zero, because it is only ever incremented in mlx5echannelstatsalloc(), which is reached only from mlx5eopenchannel(). mlx5ehvvhcastatsbufsize() therefore returns 0, and kvzalloc(0, GFPKERNEL) returns ZEROSIZEPTR ((void )16) rather than NULL. The "if (!buf)" guard does not catch this, and mlx5ehvvhcastatscreate() completes "successfully" with priv->statsagent.buf set to ZEROSIZEPTR. Once channels are opened (priv->statsnch > 0) and the hypervisor enables stats reporting, mlx5ehvvhcastatswork() recomputes buflen using the new non-zero statsnch and calls memset(buf, 0, buflen) on ZEROSIZEPTR, faulting at address 0x10. Allocate the buffer based on priv->maxnch, which is set in mlx5eprivinit() and is the upper bound on statsnch: - Add a separate helper mlx5ehvvhcastatsbufmaxsize() that returns sizeof(perringstats) max(maxnch, statsnch), and use it for the kvzalloc() in mlx5ehvvhcastatscreate(). - Keep mlx5ehvvhcastatsbufsize() (which returns based on statsnch) for the worker's active payload size, so the wire format (block->rings = statsnch) and the amount of data filled by mlx5ehvvhcafillstats() are unchanged. The max(maxnch, statsnch) guard handles the rare case where mlx5eattachnetdev() recomputes maxnch downward across a detach/resume cycle while priv->statsnch persists (mlx5edetachnetdev does not call mlx5eprivcleanup, so statsnch is only reset when the netdev is destroyed). Without the guard, the worker could compute buflen from statsnch and overrun the smaller buffer allocated based on the reduced maxnch. Allocating a non-zero buffer also makes the kvzalloc() failure path in mlx5ehvvhcastatscreate() reachable for the first time: it returns early without (re)creating the agent. Clear priv->statsagent.{agent,buf} in mlx5ehvvhcastatsdestroy() after freeing them, so that if a later create() bails out on this path, a subsequent teardown does not double-free the stale agent/buffer left from a previous enable/disable cycle. This mirrors the existing mlx5e pattern of preallocating arrays of size maxnch (e.g. priv->channelstats) and lazily populating entries up to statsnch on demand.
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
Event History
Frequently Asked Questions
Which systems are exposed to this issue?
Systems using the affected Ubuntu kernel packages are exposed when the mlx5e network driver is in use and Hyper-V VHCA statistics reporting is enabled. The listed packages include linux-riscv, linux-realtime, linux-azure, linux-gcp, linux-azure-fde, linux-gke, linux-hwe-edge, and linux-gkeop.
What conditions trigger the failure?
The driver must create HV VHCA statistics before network channels are opened, leaving its statistics buffer as a zero-size allocation. After channels are opened, enabling hypervisor statistics reporting causes the driver to clear that invalid buffer and fault at address 0x10.
What is the operational impact?
The described result is a kernel fault when the statistics worker calls memset on the zero-size buffer pointer. This can disrupt the affected system's network-driver operation and availability.
What change fixes the issue?
The fix allocates the HV VHCA statistics buffer using max_nch, the upper bound for the number of statistics channels, rather than the initially zero stats_nch value.