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CVE-2026-72495
RDMA/bnxt_re: Avoid repeated requests to allocate WC pages
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-2026-72495 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
Applications can request multiple WC pages for the same ucontext. As of now, only 1 WC page per ucontext is supported. Add a lock to avoid concurrent access and a check to fail repeated requests. Also, if the mmap entry insert fails for the WC, free the Doorbell page index mapped for the WC page.
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
drivers/infiniband/hw/bnxt_re/ib_verbs.h
drivers/infiniband/hw/bnxt_re/uapi.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
- 9.3 critical
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.19%, higher than 8.4% 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 | 6.18.40 | 478c4d24193f |
| 6.5 | 7.1.5 | da406b8b49c1 |
| 6.5 | 7.2 | 441baa790434 |
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 in BNXT_RE_METHOD_ALLOC_PAGE, reached only via write/ioctl on /dev/infiniband/uverbs* after IB ucontext creation; remote RoCE packet handling and in-kernel RDMA target/server paths never invoke this WC DPI allocation routine.
- AC:LAttack complexity, low
- An attacker can deterministically trigger the bug by issuing repeated or concurrent BNXT_RE_ALLOC_WC_PAGE calls from multiple threads on the same ucontext; they control both sides of the race and need no uncontrollable memory layout or victim-specific state.
- PR:NPrivileges required, none
- Standard uverbs character devices are created mode 0666, so any local process can open the bnxt_re device, allocate a ucontext, and invoke BNXT_RE_METHOD_ALLOC_PAGE without CAP_SYS_ADMIN, init-namespace root, or other elevated capabilities.
- UI:NUser interaction, none
- No victim interaction is required; exploitation needs only the attacker (or a compromised local RDMA workload) repeatedly or concurrently calling ALLOC_PAGE on resources it already controls through normal RDMA verbs.
- S:CScope, changed
- On HPC/cloud hosts exposing bnxt_re to tenant containers or unprivileged RDMA workloads, corrupting shared per-device DPI bookkeeping or exhausting finite doorbell indices crosses the container/tenant boundary to impact the host/kernel security authority.
- C:HConfidentiality impact, high
- Without serialization or duplicate checks, corrupt DPI index bookkeeping and premature slot reuse can alias WC doorbell BAR pages across contexts, exposing other users' doorbell state and providing resource-corruption primitives usable for information disclosure.
- I:HIntegrity impact, high
- Destroying one ALLOC_PAGE object can deallocate another object's live WC DPI slot while its BAR mmap remains active, letting a later allocation share the same doorbell page and enabling cross-context WC doorbell writes that corrupt other tenants' RDMA queue signaling.
- A:HAvailability impact, high
- Each orphaned DPI entry permanently consumes a finite per-device doorbell index (exhaustible via repeated or concurrent ALLOC_PAGE), denying RDMA service cluster-wide; unsynchronized wcdpi updates can also destabilize kernel DPI teardown paths.