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CVE-2026-72499
RDMA/bnxt_re: Free CQ toggle page after firmware teardown
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem drivers/infiniband. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-72499 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 | not affected | 6.1.190-1 | Nothing to do. bookworm never shipped the vulnerable code. |
| Debian 13trixie | vulnerable | 6.12.113-1 | No fix published anywhere yet, neither in Debian nor upstream for the series trixie tracks. Watch the Debian tracker page for this CVE. Advisories for trixie have historically landed a median of 11 days after publication. |
| 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
Free the toggle page only after firmware teardown completes so that an NQ interrupt arriving during bnxt_qplib_destroy_cq() won't write the toggle value to an already-freed page. Move free_page() after bnxt_qplib_destroy_cq.
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/bnxt_re/ib_verbs.c
- What this is
- BROADCOM NETXTREME-E ROCE DRIVERMAINTAINERS section matched on drivers/infiniband/hw/bnxt_re/ · linux-rdma@vger.kernel.org · Supported
- Kernel module
- bnxt_re
Check it on the machine
grep -wE 'CONFIG_INFINIBAND|CONFIG_INFINIBAND_BNXT_RE' /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 bnxt_rePrints 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 does not build this code in 1 release. It does build it in 3 releases, so the answer depends on which release the machine runs.
- bookwormn
- trixieMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp
- forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armhf/armmp, armhf/armmp-lpae
- n
- not enabled on any flavour - this release does not build the code
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_INFINIBAND, CONFIG_INFINIBAND_BNXT_RE
- 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
- 8.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.17%, higher than 6.3% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- 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 |
|---|---|---|
| 6.8 | 6.18.57 | 33aed3ba04aa |
| 6.8 | 7.1.5 | b193854675ec |
| 6.8 | 7.2 | bb45e06f9914 |
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
- The bug is triggered by destroying a user CQ through the RDMA uverbs ioctl on /dev/infiniband/uverbs*; although RoCE peers can generate CQ/NQ events, the premature free_page() only occurs in this local destroy path, not from remote packet handling alone.
- AC:LAttack complexity, low
- An attacker controls CQ teardown timing via ibv_destroy_cq and can reliably create the race by keeping QPs active and/or soliciting CQ notifications (including from a cooperating RoCE peer) while destroy_cq runs through bnxt_qplib_destroy_cq firmware teardown.
- PR:LPrivileges required, low
- Exploitation requires only local RDMA verbs access to create/destroy a user CQ on a Gen P7 bnxt_re device; uverbs char devices are created world-accessible (0666) and RDMA is commonly granted to unprivileged HPC/cloud/Kubernetes workload users rather than real root.
- UI:NUser interaction, none
- No victim interaction is required beyond the attacker (or compromised local workload) invoking CQ destroy on resources it already controls; remote peers may assist timing but do not need the victim to click, mount, or open files.
- S:CScope, changed
- On Kubernetes/HPC hosts that expose bnxt_re to containers/pods, triggering this host-kernel UAF from an unprivileged RDMA-enabled workload can corrupt host memory and enable container-to-host sandbox escape beyond the workload security boundary.
- C:HConfidentiality impact, high
- This is a kernel write-after-free: an NQ interrupt writes a toggle value into a page already returned to the buddy allocator, enabling corruption of subsequently reallocated kernel objects and classic UAF-based information disclosure primitives.
- I:HIntegrity impact, high
- The interrupt path performs a controlled 4-byte write to freed kernel memory during destroy_cq, providing a heap corruption primitive that can be developed into arbitrary kernel write or code execution rather than being limited to a benign crash.
- A:HAvailability impact, high
- Writing to a freed page during interrupt handling can oops/panic the kernel immediately, and repeated CQ create/destroy cycles let an attacker reliably induce host-level denial of service on RDMA-enabled systems.