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CVE-2026-93037
RDMA/hfi1: Propagate sdma_txinit_ahg() errors
Published 2026-09-17 (31 days 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-2026-93037 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 | fixedDLA-4841-1 · 2026-10-17 · text | 6.1.190-1 | Update the kernel and reboot. DLA-4841-1 shipped the fix on 2026-10-17, in 6.1.190-1. A running kernel keeps the old code until the machine restarts. |
| 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 | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. 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
set_txreq_header_ahg() ignores the return value of sdma_txinit_ahg(). If sdma_txinit_ahg() fails, it returns before initializing tx->txreq. However, set_txreq_header_ahg() ignores the error and returns the AHG change count, causing the caller to continue processing the request as though initialization had succeeded. Propagate sdma_txinit_ahg() failures to the caller and abort request processing when initialization fails. Found by Linux Verification Center (linuxtesting.org) with SVACE.
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/hfi1/user_sdma.c
- What this is
- HFI1 DRIVERMAINTAINERS section matched on drivers/infiniband/hw/hfi1 · linux-rdma@vger.kernel.org · Supported
- Kernel module
- hfi1
Check it on the machine
grep -wE 'CONFIG_INFINIBAND|CONFIG_INFINIBAND_HFI1' /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 hfi1Prints 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.
- bookwormMnot built on amd64/cloud-amd64, arm64/arm64, arm64/cloud-arm64, arm64/rt/arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, i386/686, i386/686-pae, i386/rt/686-pae, ppc64el/powerpc64le
- trixieMnot built on amd64/cloud-amd64, arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt/arm64, armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- forky, sidMnot built on amd64/cloud-amd64, arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt-arm64, armhf/armmp, armhf/armmp-lpae, loong64/loong64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- bookworm · linux-6.12Mnot built on amd64/cloud-amd64, arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt/arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_INFINIBAND, CONFIG_INFINIBAND_HFI1
- 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
- 2026-09-17 (31 days 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
- 0.16%, higher than 5.3% 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 |
|---|---|---|
| 4.14 | 5.10.270 | cb73c2fe6e9c |
| 4.14 | 5.15.221 | 122a73067556 |
| 4.14 | 6.1.188 | bf974994150c |
| 4.14 | 6.6.157 | fd6dee13f385 |
| 4.14 | 6.12.110 | 5b7cefffd15d |
| 4.14 | 6.18.52 | 3416db552eb3 |
| 4.14 | 7.2.6 | ca99431820e8 |
| 4.14 | 7.3 | 091c6162c022 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4841-1 | 2026-10-17 | bookworm 6.1.190-1 | tracker |
| 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 attacker-controlled bytes are the sdma_req_info/header/iovecs copy_from_user()'d in hfi1_user_sdma_process_request(), reached only from hfi1_write_iter() on the hfi1 user cdev. A remote Omni-Path peer does not supply that request; kernel verbs already check sdma_txinit_ahg() and are not this bug.
- AC:LAttack complexity, low
- On the AHG path (npkts>1 and HFI1_CAP_IS_USET(SDMA_AHG) so ahg_idx>=0), the attacker sets a later packet's datalen to 0 or info.fragsize>MAX_SDMA_PKT_SIZE so sdma_txinit_ahg() returns -ENODATA/-EMSGSIZE. set_txreq_header_ahg() still returns the AHG index count, and user_sdma_send_pkts() continues with no race.
- PR:LPrivileges required, low
- hfi1_user_devnode() creates /dev/hfi1_N with mode 0666, and hfi1_file_open()/assign_ctxt() perform no capability checks, so an ordinary unprivileged local user can assign a context and writev() the crafted SDMA request.
- UI:NUser interaction, none
- Exploitation is the attacker's own open, HFI1_IOCTL_ASSIGN_CTXT, and writev() of a multi-packet user SDMA request; no other user must mount media, open a file, or otherwise interact.
- S:UScope, unchanged
- The uninitialized user_sdma_txreq.txreq is consumed by make_tx_sdma_desc() and submit_tx() inside the host hfi1 driver; impact is host-kernel memory/DMA corruption, not a guest-to-host, IOMMU, or other authority-boundary escape.
- C:HConfidentiality impact, high
- user_sdma_send_pkts() still calls hfi1_add_pages_to_sdma_packet() after the failed sdma_txinit_ahg(), and make_tx_sdma_desc() reads/writes through uninitialized tx->descp. A recycled txreq_cache object whose extended descp was kfree'd in __sdma_txclean() is a use-after-free, enabling kernel info disclosure.
- I:HIntegrity impact, high
- make_tx_sdma_desc() writes DMA address and length through that uninitialized/dangling descp, and submit_tx() copies those descriptors into the SDMA ring. That is an arbitrary kernel write and hardware DMA of attacker-influenced descriptors, enabling control-flow hijack.
- A:HAvailability impact, high
- submit_tx() always loads descp->qw[0] even when num_desc is 0, so a NULL descp from an uninitialized txreq is a kernel NULL-deref oops; garbage num_desc/descriptors also crash or halt the SDMA engine.