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CVE-2026-64020
nvme-pci: fix dma_vecs leak on p2p memory
Published 2026-07-19 (3 months ago) by the Linux kernel CNA. Subsystem drivers/nvme. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-64020 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 | 7.0.12-1 | Update the kernel and reboot. Fixed in 7.0.12-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.0.12-1 | Update the kernel and reboot. Fixed in 7.0.12-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
We don't unmap P2P memory, so we don't need to track it. The dma_vec allocation was getting leaked on the completion.
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/nvme/host/pci.c
- What this is
- NVM EXPRESS DRIVERMAINTAINERS section matched on drivers/nvme/host/ · linux-nvme@lists.infradead.org · Supported
- Kernel module
- nvme
Check it on the machine
grep -w CONFIG_BLK_DEV_NVME /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 nvmePrints 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.
- bookwormb
- trixieBnot built on armel/rpi
- forky, sidb
- b
- built in on some flavours, a module on others
- B
- built in on some, a module on others, absent on the rest
- Build switch
- CONFIG_BLK_DEV_NVME
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
- 2026-07-19 (3 months ago)source
- CVSS
- 7.5 high
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsource recompute it - Attack vector
- network (AV:N)source
- EPSS
- 0.61%, higher than 48.1% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- Subsystem
- drivers/nvme
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.17 | 6.18.57 | b9390aa62fdc |
| 6.17 | 7.0.11 | 24ea0de233d9 |
| 6.17 | 7.1 | 85686c72966c |
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:NAttack vector, network
- On NVMe-oF storage servers with p2pmem-enabled namespaces backed by local PCIe NVMe, a remote client can trigger this via nvmet-tcp read/write commands that flow through submit_bio() into nvme-pci P2P PRP setup and completion.
- AC:LAttack complexity, low
- Once the P2P-capable NVMe/IOMMU configuration is present, a single crafted read or write reliably leaks the dma_vecs allocation; no races or special memory layout are required.
- PR:NPrivileges required, none
- Remote exploitation via nvmet-tcp requires no local privileges on the target when in-band authentication is not configured, matching pre-authentication network service guidance for fabric targets.
- UI:NUser interaction, none
- Exploitation is achieved entirely through NVMe I/O commands and requires no victim interaction beyond the attacker (or their client) initiating storage operations.
- S:UScope, unchanged
- The vulnerability causes kernel memory leakage and NVMe I/O denial within the same kernel security boundary; it does not cross VM, container, or IOMMU isolation boundaries.
- C:NConfidentiality impact, none
- This is a kmalloc/mempool leak with no out-of-bounds read, use-after-free, or information disclosure; freed dma_vecs tracking memory is not exposed to the attacker.
- I:NIntegrity impact, none
- No memory corruption, arbitrary write, or code execution primitive is created; impact is limited to resource exhaustion and I/O failure.
- A:HAvailability impact, high
- Each triggering completion permanently exhausts the single-element dmavec mempool, causing persistent BLK_STS_RESOURCE failures that deny subsequent P2P and non-IOVA PRP I/O on the affected NVMe controller until reboot.