CVE-2026-74395: RDMA/mlx5: Fix devx subscribe-event unwind NULL dereference
In the Linux kernel, the following vulnerability has been resolved:
RDMA/mlx5: Fix devx subscribe-event unwind NULL dereference
MLX5IBMETHODDEVXSUBSCRIBEEVENT() links eventsub into sublist before initializing the fields used by the shared error path.
If eventfdctxfdget() then fails, the unwind path dereferences eventsub->evfile in uverbsuobjectput() and calls subscribeeventxadealloc() with an unset xakeylevel1.
subscribeeventxaalloc() creates the XA entry exactly once for a given keylevel1, on the first occurrence of that key. The unwind path must therefore call subscribeeventxadealloc() exactly once for it as well.
Enforce that by adding devxkeyinsublist() and calling subscribeeventxadealloc() only when the last matching pending entry is being cleaned up.
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-azureto a version that resolves this vulnerability.Fixed in 6.8.0-1071.79 - 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-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
In the Linux kernel RDMA/mlx5 devx subscribe-event unwind path, add devx_key_in_sub_list() and call subscribe_event_xa_dealloc() exactly once, only when the last matching pending entry is being cleaned up, including when eventfd_ctx_fdget() fails.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-74395?
CVE-2026-74395 is classified with a risk score of 24.
What causes CVE-2026-74395?
CVE-2026-74395 is caused by a NULL dereference when unwinding the subscribed event in the RDMA/mlx5 driver.
How do I fix CVE-2026-74395?
To fix CVE-2026-74395, you need to apply the latest kernel updates that address the vulnerability.
What systems are affected by CVE-2026-74395?
CVE-2026-74395 affects systems utilizing the Linux kernel with the RDMA/mlx5 driver.
Has CVE-2026-74395 been resolved?
Yes, CVE-2026-74395 has been resolved in recent kernel patches released on August 15, 2026.