Look up another CVE · open CVE-2026-74297 in the interactive tracker
CVE-2026-74297
RDMA/mlx5: Fix undefined shift of user RQ WQE size
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem drivers/infiniband. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-74297 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | fixed | 6.1.180-1 | Update the kernel and reboot. Fixed in 6.1.180-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.100-1 | Update the kernel and reboot. Fixed in 6.12.100-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
set_rq_size() computes the RQ WQE size as "1 << rq_wqe_shift" based on the user-provided rq_wqe_shift, which is only checked to be greater than 32, so shifts of 32 are still accepted. A shift of 31 also overflows a signed integer, leading to undefined behavior. Use check_shl_overflow() to compute the RQ WQE size and reject any invalid values.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
drivers/infiniband/hw/mlx5/qp.c
- What this is
- MELLANOX MLX5 IB driverMAINTAINERS section matched on drivers/infiniband/hw/mlx5/ · linux-rdma@vger.kernel.org · Supported
- Kernel module
- mlx5_ib
Check it on the machine
grep -wE 'CONFIG_INFINIBAND|CONFIG_MLX5_INFINIBAND' /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
lsmod | grep -w mlx5_ibPrints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.
Show whether Debian builds this, per release
Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.
- bookwormm
- trixieMnot built on armel/rpi
- forky, sidm
- m
- a loadable module on every flavour - check lsmod, can be blacklisted
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_INFINIBAND, CONFIG_MLX5_INFINIBAND
- Reads as
- all on means the file is compiled; any one off means it is not.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-08-15 (2 months ago)source
- CVSS
- 7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.18%, higher than 6.6% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/infiniband
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 3.11 | 5.10.261 | 9fff54929cc0 |
| 3.11 | 5.15.212 | b746f949c2ac |
| 3.11 | 6.1.178 | c1dbf52d24a8 |
| 3.11 | 6.6.145 | 6fc874fdfb36 |
| 3.11 | 6.12.97 | 42f3d2c8c18b |
| 3.11 | 6.18.40 | 4b87a2497276 |
| 3.11 | 7.1.5 | b732db02a2b0 |
| 3.11 | 7.2 | d881d60223aa |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- Exploitation requires a local ioctl on /dev/infiniband/uverbs to IB_USER_VERBS_CMD_CREATE_QP; malicious rq_wqe_shift is supplied in mlx5_ib_create_qp userspace data, not from remote RDMA/InfiniBand wire traffic.
- AC:LAttack complexity, low
- An attacker with uverbs access can deterministically pass rq_wqe_shift values 31 or 32 in create_qp driver udata; no races or victim state beyond opening the device and issuing the ioctl are required.
- PR:LPrivileges required, low
- Only local access to the RDMA character device is required (typically rdma group membership on HPC/AI cloud GPU nodes), not init-namespace root; this matches basic local user capability rather than administrator privilege.
- UI:NUser interaction, none
- No victim interaction is needed; the attacker triggers the flaw entirely through their own create_qp ioctl with crafted mlx5_ib_create_qp fields.
- S:UScope, unchanged
- Impact stays within the kernel and RDMA context of the attacking process/tenant; it is not a VM-hypervisor or cross-security-authority boundary escape despite using a network-capable NIC.
- C:HConfidentiality impact, high
- Integer overflow/undefined shift can undersize ib_umem registration while hardware is programmed with a huge RQ stride, enabling out-of-bounds DMA reads and kernel/user memory disclosure beyond the registered queue buffer.
- I:HIntegrity impact, high
- Corrupted max_gs (e.g. negative from shift 31) bypasses scatter/gather limits in post_recv, and undersized buffers with oversized hardware stride allow out-of-bounds writes and exploitable memory corruption.
- A:HAvailability impact, high
- Undefined signed shifts and inconsistent queue sizing can cause kernel oops/panic during QP setup or later queue operations, and misprogrammed hardware can hang or crash the host under active RDMA use.