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CVE-2026-89594
hsi: omap_ssi_core: fix missing DMA mask setup for SSI controller device
Published 2026-09-11 (37 days ago) by the Linux kernel CNA. Subsystem drivers/hsi. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-89594 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
The OMAP SSI driver uses a synthetic HSI controller device allocated via hsi_alloc_controller(), which does not go through the normal OF/platform device initialization path. As a result, the embedded struct device does not have a DMA mask initialized by default. After recent DMA API hardening changes, dma_map_sg() and related helpers now require a valid dma_mask to be present, otherwise the driver may crash or trigger warnings when attempting DMA mapping operations. Fix this by explicitly initializing the DMA mask for the SSI controller device and setting a 32-bit DMA mask, which matches the hardware capabilities.
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/hsi/controllers/omap_ssi_core.c
- What this is
- HSI SUBSYSTEMMAINTAINERS section matched on drivers/hsi/ · Maintained
- Kernel module
- omap_ssi
Check it on the machine
grep -wE 'CONFIG_HSI|CONFIG_OMAP_SSI' /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 omap_ssiPrints 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/amd64, amd64/cloud-amd64, amd64/rt/amd64, arm64/arm64, arm64/cloud-arm64, arm64/rt/arm64, i386/686, i386/686-pae, i386/rt/686-pae, ppc64el/powerpc64le
- trixieMnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt/amd64, arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt/arm64, armel/rpi, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- forky, sidMnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt-amd64, arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt-arm64, loong64/loong64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- bookworm · linux-6.12Mnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt/amd64, arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt/arm64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_HSI, CONFIG_OMAP_SSI
- 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
- 2026-09-11 (37 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
- 0.17%, higher than 5.8% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/hsi
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.10 | 5.10.270 | 6a5426f56de9 |
| 5.10 | 5.15.221 | a4beb841f84e |
| 5.10 | 6.1.188 | 9ecef057b7a7 |
| 5.10 | 6.6.157 | 9963a65be2be |
| 5.10 | 6.12.109 | e8d47e309c70 |
| 5.10 | 6.18.50 | 4e019e5e247b |
| 5.10 | 7.2.4 | fbffbfdae559 |
| 5.10 | 7.3 | e81250ec6b69 |
| 5.9.2 | 0 | 0 |
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 OMAP SSI HSI controller is an on-SoC serial engine used as the Nokia N900/RX-51 modem link. dma_map_sg() on the synthetic controller device is reached from local hsi_char I/O, cmt_speech, or ssi_protocol/phonet transfers, not from the network stack or a pluggable USB/Bluetooth device.
- AC:LAttack complexity, low
- Any SSI payload longer than 4 bytes takes ssi_start_dma()→dma_map_sg() on ssi->device, whose dma_mask is NULL after hsi_alloc_controller(). The WARN/oops is deterministic; the attacker does not need a race or an uncontrollable memory layout.
- PR:LPrivileges required, low
- hsi_char open/read/write has no capability check. On the intended OMAP3 phone deployment an unprivileged user can also drive SSI DMA through the cellular/phonet modem stack. Direct AF_PHONET sockets need CAP_SYS_ADMIN, which is not required for this highest-impact local path.
- UI:NUser interaction, none
- The attacker starts the SSI transfer or modem activity themselves; no separate victim must mount a filesystem, plug in a device, or otherwise cooperate.
- S:UScope, unchanged
- The oops, panic, and any GDD completion on the stale hsi_msg stay in the host kernel. Mapping is rejected rather than issuing IOMMU-bypassing DMA, so this is not a VM escape or DMA-boundary bypass.
- C:HConfidentiality impact, high
- ssi_claim_lch() leaves the hsi_msg in gdd_trn after dma_map_sg() fails and ssi_async() returns that message to the client, so the observed ssi_gdd_complete()/ssi_gdd_tasklet oops is a use-after-unlink of a kernel DMA object, treated as a high-impact read primitive.
- I:HIntegrity impact, high
- The same leftover GDD claim lets completion list_del, dma_unmap_sg, and complete a message the client already reused or freed, corrupting kernel lists and object state; the reporter also hit an L3 interconnect abort and a NULL-pointer store in interrupt context.
- A:HAvailability impact, high
- The original N900 report shows WARN_ON in dma_map_sg, an L3 nobody-cared IRQ storm, a NULL deref in ssi_gdd_tasklet, and Kernel panic - not syncing: Fatal exception in interrupt.