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CVE-2026-53160
misc: fastrpc: fix use-after-free race in fastrpc_map_create
Published 2026-06-25 (4 months ago) by the Linux kernel CNA. Subsystem drivers/misc. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-53160 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-4665-1 · 2026-07-03 · text | 6.1.176-1 | Update the kernel and reboot. DLA-4665-1 shipped the fix on 2026-07-03, in 6.1.176-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.94-1 | Update the kernel and reboot. Fixed in 6.12.94-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.0.13-1 | Update the kernel and reboot. Fixed in 7.0.13-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.0.13-1 | Update the kernel and reboot. Fixed in 7.0.13-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
fastrpc_map_lookup returns a raw pointer after releasing fl->lock. The caller fastrpc_map_create then calls fastrpc_map_get (kref_get_unless_zero) on this unprotected pointer. A concurrent MEM_UNMAP can free the map between the lock release and the kref operation, resulting in a use-after-free on the freed slab object. Restore the take_ref parameter to fastrpc_map_lookup so the reference is acquired atomically under fl->lock before the pointer is exposed to the caller.
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/misc/fastrpc.c
- What this is
- QUALCOMM FASTRPC DRIVERMAINTAINERS section matched on drivers/misc/fastrpc.c · linux-arm-msm@vger.kernel.org · Maintained
- Kernel module
- fastrpc
Check it on the machine
grep -w CONFIG_QCOM_FASTRPC /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 fastrpcPrints 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/amd64, amd64/cloud-amd64, amd64/rt/amd64, arm64/cloud-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/amd64, amd64/cloud-amd64, amd64/rt-amd64, arm64/cloud-arm64, armhf/armmp, armhf/armmp-lpae, loong64/loong64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- 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 switch
- CONFIG_QCOM_FASTRPC
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
- 2026-06-25 (4 months 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
- 0.13%, higher than 2.0% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/misc
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.1.156 | 6.1.176 | 0a3b87293fbd |
| 6.6.112 | 6.6.143 | 8b080c891831 |
| 6.12.53 | 6.12.94 | 5b0166112019 |
| 6.18 | 6.18.36 | 992f121796b7 |
| 6.18 | 7.0.13 | f20f6512ecb7 |
| 6.18 | 7.1 | 07ebe87915d8 |
| 6.17.3 | 0 | 0 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4671-1 | 2026-07-05 | bullseye 6.1.176-1~deb11u1 | tracker |
| DLA-4665-1 | 2026-07-03 | bookworm 6.1.176-1 | 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 vulnerable code is reached through local FastRPC misc-device ioctls such as FASTRPC_IOCTL_MEM_MAP, FASTRPC_IOCTL_INVOKE, and FASTRPC_IOCTL_INIT_CREATE. There is no network or adjacent-path entry point.
- AC:LAttack complexity, low
- The attacker can drive both sides of the race by issuing concurrent map-creating and MEM_UNMAP ioctls against the same FastRPC file context and DMA-buf fd. No condition outside attacker control is required beyond scheduling the race.
- PR:LPrivileges required, low
- The ioctl path has no in-driver capable(), namespace capability, or credential check once the FastRPC device node is open. Exploitation requires local access to the device node as a basic user or device-authorized app, not real root.
- UI:NUser interaction, none
- No victim action is required after the attacker has local access. The attacker directly opens the FastRPC device and submits ioctls.
- S:UScope, unchanged
- This is a kernel memory safety bug in a local kernel driver and exploitation would affect the same kernel security authority. It is not a VM escape, IOMMU bypass, or other cross-scope boundary violation by itself.
- C:HConfidentiality impact, high
- The bug is a use-after-free on struct fastrpc_map, a slab object containing pointers and DMA mapping state. Under the required high-severity rule, this memory corruption is treated as capable of enabling kernel information disclosure.
- I:HIntegrity impact, high
- The use-after-free can be raced with allocator reuse and involves refcount/list/DMA mapping state, making control of freed object contents plausibly exploitable for kernel memory corruption. Under the kernel guidance, UAFs receive high integrity impact.
- A:HAvailability impact, high
- Even without full exploitation, racing kref_get_unless_zero() and later map-field use on a freed object can trigger kernel warnings, oopses, or crashes. Repeated local ioctls can therefore cause high availability impact.