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CVE-2026-72496
RDMA/bnxt_re: Proper rollback if the ioremap fails
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-2026-72496 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 | fixedDSA-6528-1 · 2026-09-29 · text | 6.12.111-1 | Update the kernel and reboot. DSA-6528-1 shipped the fix on 2026-09-29, in 6.12.111-1. 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. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4817-1 · 2026-10-04 · text | 6.12.111-1~deb12u1 | Update the kernel and reboot. DLA-4817-1 shipped the fix on 2026-10-04, in 6.12.111-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
bnxt_qplib_alloc_dpi returns success even if ioremap fails. Add the proper rollback when the ioremap fails and return -ENOMEM status.
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/qplib_res.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 4 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
- bookworm · linux-6.12Mnot built on amd64/cloud-amd64, arm64/cloud-arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp
- 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
- 9.2 critical
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.14%, higher than 2.8% 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 |
|---|---|---|
| 6.5 | 6.6.158 | 00444baa8f74 |
| 6.5 | 6.12.111 | 3c69ff7f4a76 |
| 6.5 | 6.18.53 | f956477c343a |
| 6.5 | 7.1.5 | 303f6fef95df |
| 6.5 | 7.2 | 87267803a8c8 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4817-1 | 2026-10-04 | bookworm 6.12.111-1~deb12u1 | tracker |
| DSA-6528-1 | 2026-09-29 | trixie 6.12.111-1 | tracker |
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 flaw is reached only through local RDMA uverbs ioctl/write on /dev/infiniband/uverbs* (ibv_alloc_pd and BNXT_RE_ALLOC_WC_PAGE call bnxt_qplib_alloc_dpi); remote RoCE packet handling and in-kernel RDMA target/server paths never invoke this DPI setup routine.
- AC:LAttack complexity, low
- An attacker can induce vmalloc/ioremap failure with local memory pressure, then repeatedly invoke alloc_pd or WC-page allocation; each call deterministically leaves a consumed DPI with NULL dbr, and subsequent create_cq/QP/SRQ doorbell rings fault without races or uncontrollable layout.
- PR:NPrivileges required, none
- ib_uverbs creates per-device character nodes as mode 0666, so any local process can open uverbs, allocate a context, and call alloc_pd or alloc_page without CAP_SYS_ADMIN, init-namespace root, or other elevated capabilities on typical HPC/cloud RDMA hosts.
- UI:NUser interaction, none
- Exploitation requires only the attacker's own RDMA verbs sequence (alloc_context, alloc_pd or alloc_page, then create_cq/QP/SRQ and I/O); no cooperative action by another user, administrator, or victim mounting devices or opening files is needed.
- S:CScope, changed
- On Kubernetes/HPC hosts exposing bnxt_re to tenant containers or unprivileged RDMA workloads, triggering host-kernel NULL doorbell writes or exhausting finite DPI indices from a workload crosses the container/tenant security boundary to the hypervisor/host authority.
- C:LConfidentiality impact, low
- Returning success after failed ioremap leaves DPI metadata and a mmapable BAR doorbell offset active while kernel dpi->dbr stays NULL, disclosing doorbell-index/BAR layout to the caller and enabling follow-on corruption when doorbells are later rung.
- I:HIntegrity impact, high
- With dpi->dbr left NULL, bnxt_qplib_ring_db and ring_prod_db issue writeq() to NULL during CQ, SQ, RQ, and SRQ doorbell updates on subsequent verbs activity, providing a kernel write primitive and control-flow disruption beyond a benign error return.
- A:HAvailability impact, high
- NULL doorbell writeq faults oops or panic the kernel when CQ/QP/SRQ objects are used after the bogus allocation, and each successful-but-broken DPI allocation permanently consumes a finite doorbell index, enabling repeated denial of RDMA service to other tenants.