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CVE-2026-81004
ipmi:msghandler: Cancel work cleanly on an error
Published 2026-09-11 (37 days ago) by the Linux kernel CNA. Subsystem drivers/char. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-81004 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 | not affected | 6.12.113-1 | Nothing to do. trixie never shipped the vulnerable code. |
| 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. |
The vulnerability
What the bug is
If an error occurs during startup of an IPMI interface, it may have scheduled work to run. The work needs to be canceled before the interface can be freed.
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/char/ipmi/ipmi_msghandler.c
- What this is
- IPMI SUBSYSTEMMAINTAINERS section matched on drivers/char/ipmi/ · openipmi-developer@lists.sourceforge.net · Supported
- Kernel module
- ipmi_msghandler
Check it on the machine
grep -w CONFIG_IPMI_HANDLER /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 ipmi_msghandlerPrints 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/cloud-arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp
- trixieMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, riscv64/riscv64, s390x/s390x
- forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armhf/armmp, armhf/armmp-lpae, loong64/loong64, riscv64/riscv64, s390x/s390x
- M
- a module where it is built at all; some flavours do not build it
- Build switch
- CONFIG_IPMI_HANDLER
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
- 8.4 high
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.18%, higher than 6.9% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- Subsystem
- drivers/char
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.18.20 | 6.18.50 | 99692252b348 |
| 7.0 | 7.2.4 | a496c51dd325 |
| 7.0 | 7.3 | ae84a2536577 |
| 6.19.10 | 0 | 0 |
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
- ipmi_add_smi() is reached from host-local IPMI system-interface probe (ipmi_si/SSIF/IPMB/PowerNV), not from Linux network-packet processing; a compromised BMC still talks over KCS/SMIC/BT/SSIF/IPMB on the platform, so the attack remains local.
- AC:LAttack complexity, low
- When the lower-layer sender() fails during startup Get Device ID or channel scan, smi_send() queues intf->smi_work and returns an error; ipmi_add_smi() then frees the interface without cancel_work_sync, so a BMC that returns a bus error deterministically leaves work pending on a freed object.
- PR:NPrivileges required, none
- The vulnerable path runs during automatic SMI registration at boot or device probe; a compromised BMC can fail sender() or Get Device ID after work is queued with no host login, capability, or /dev/ipmiN access.
- UI:NUser interaction, none
- Driver probe and BMC responses occur without a victim mounting a filesystem, opening a device node, or otherwise interacting.
- S:UScope, unchanged
- The use-after-free is of host-kernel struct ipmi_smi in the IPMI message handler; it is a standard in-kernel UAF, not a VM escape, IOMMU bypass, or sandbox breakout.
- C:HConfidentiality impact, high
- smi_work() recovers the freed ipmi_smi via from_work and reads its queues, flags, and handler pointers from reclaimed slab memory, yielding an arbitrary kernel read primitive per UAF guidance.
- I:HIntegrity impact, high
- smi_work() invokes intf->handlers->sender on the freed interface, so a heap-sprayed object can hijack that function pointer for arbitrary write and control-flow hijack.
- A:HAvailability impact, high
- Running queued smi_work after kfree(intf) in intf_free() dereferences freed memory and readily oopses or panics the kernel.