CVE-2023-53273: Drivers: vmbus: Check for channel allocation before looking up relids

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-09-16 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: Drivers: vmbus: Check for channel allocation before looking up relids relid2channel() assumes vmbus channel array to be allocated when called. However, in cases such as kdump/kexec, not all relids will be reset by the host. When the second kernel boots and if the guest receives a vmbus interrupt during vmbus driver initialization before vmbus_connect() is called, before it finishes, or if it fails, the vmbus interrupt service routine is called which in turn calls relid2channel() and can cause a null pointer dereference. Print a warning and error out in relid2channel() for a channel id that's invalid in the second kernel.

Affected products

Linux kernel: from 5.8 before 5.10.178; from 5.11 before 5.15.107; from 5.16 before 6.1.24; from 6.2 before 6.2.11; 6.3-rc1, 6.3-rc2, 6.3-rc3, 6.3-rc4, 6.3-rc5 — fixed in 5.10.178, 5.15.107, 6.1.24, 6.2.11

How to fix

Upgrade to a fixed version: Linux kernel 5.10.178, 5.15.107, 6.1.24, 6.2.11. Check the vendor advisory for mitigations.

References

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