CVE-2026-89505: RDMA/uverbs: Guard legacy bundles without method_elm

Severity: unknown
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: 2026-09-11 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: RDMA/uverbs: Guard legacy bundles without method_elm The legacy write() path dispatches through a uverbs_api_write_method, but the uverbs_attr_bundle passed to provider code does not have an ioctl method element. If malformed provider input causes the common uverbs validation code to emit an error message, uverbs_get_handler_fn() dereferences the uninitialized method_elm pointer. Initialize method_elm explicitly for legacy bundles and make uverbs_get_handler_fn() return NULL when no ioctl method is present. The legacy dispatcher continues to use its local write method, while the ioctl path continues to use the registered ioctl handler.

Affected products

Linux kernel: 7.1 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux kernel 7.3. Check the vendor advisory for mitigations.

References

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