CVE-2024-40992: RDMA/rxe: Fix responder length checking for UD request packets

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-07-12 · updated 2026-08-04

Description

In the Linux kernel, the following vulnerability has been resolved: RDMA/rxe: Fix responder length checking for UD request packets According to the IBA specification: If a UD request packet is detected with an invalid length, the request shall be an invalid request and it shall be silently dropped by the responder. The responder then waits for a new request packet. commit 689c5421bfe0 ("RDMA/rxe: Fix incorrect responder length checking") defers responder length check for UD QPs in function `copy_data`. But it introduces a regression issue for UD QPs. When the packet size is too large to fit in the receive buffer. `copy_data` will return error code -EINVAL. Then `send_data_in` will return RESPST_ERR_MALFORMED_WQE. UD QP will transfer into ERROR state.

Affected products

Linux kernel: from 6.2 before 6.6.36; from 6.7 before 6.9.7; 6.10-rc1, 6.10-rc2, 6.10-rc3, 6.10-rc4 — fixed in 6.6.36, 6.9.7

How to fix

Upgrade to a fixed version: Linux kernel 6.6.36, 6.9.7. Check the vendor advisory for mitigations.

References

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