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CVE-2026-74361
nvme: fix FDP fdpcidx bounds check
Published 2026-08-15 (2 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-2026-74361 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 | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
The fdpcidx bounds check sets n = NUMFDPC + 1 but used > instead of >=, incorrectly accepting fdp_idx when it equals n (i.e. NUMFDPC + 1).
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/core.c
- What this is
- NVM EXPRESS DRIVERMAINTAINERS section matched on drivers/nvme/host/ · linux-nvme@lists.infradead.org · Supported
- Kernel module
- nvme_core
Check it on the machine
grep -w CONFIG_NVME_CORE /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 nvme_corePrints 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 code. Every release below compiles the affected file into the kernels it ships.
- bookworm, trixie, forky, sidb
- b
- built in on some flavours, a module on others
- Build switch
- CONFIG_NVME_CORE
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
- 2026-08-15 (2 months ago)source
- CVSS
- 9.8 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- network (AV:N)source
- EPSS
- 0.65%, higher than 50.1% 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 |
|---|---|---|
| 6.16 | 6.18.40 | 5e406928404d |
| 6.16 | 7.1.5 | 5d0e7d2af884 |
| 6.16 | 7.2 | 0967074f6830 |
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
- The bug is in the NVMe host driver while parsing Get Features/Get Log responses during namespace scan; a malicious NVMe-oF target can deliver crafted FDP data over TCP/RDMA to any host already using remote NVMe storage, which is the highest-impact reachable deployment.
- AC:LAttack complexity, low
- An attacker controlling the NVMe endpoint fully sets fdpcidx and numfdpc in protocol responses and can reliably make fdpcidx equal numfdpc+1, walk one descriptor past the valid list, and hit the out-of-bounds read without races or victim-specific heap layout.
- PR:NPrivileges required, none
- Exploitation needs no local account or capabilities on the victim; a remote malicious/compromised NVMe-oF target (or physical device inserted by an attacker) triggers parsing during connect/rescan/AEN-driven namespace scans without further local authorization.
- UI:NUser interaction, none
- No victim user action is required at exploit time because namespace scanning and AEN-triggered rescans run automatically in kernel workqueues once a controller is present, and a remote target can force rescans with Notice Namespace Changed events.
- S:UScope, unchanged
- Impact is confined to kernel memory and block-layer metadata on the host parsing the malicious device responses; it does not cross a VM, container, or IOMMU security boundary into a separate authority.
- C:HConfidentiality impact, high
- Accepting fdpcidx=numfdpc+1 lets the descriptor walk advance past the last valid FDP configuration and then reads desc->nrg and desc->runs out of bounds, leaking adjacent kvmalloc/heap contents or attacker-crafted bytes from beyond the valid descriptor array.
- I:HIntegrity impact, high
- The out-of-bounds descriptor fields are copied into info->runs and influence queue write_stream_granularity limits, giving attacker-controlled modification of kernel block-layer state from memory corruption primitives that can be chained beyond a simple crash.
- A:HAvailability impact, high
- If the out-of-bounds descriptor pointer lies past the allocated FDP log buffer, accessing desc->nrg/desc->runs can fault the kernel (oops/panic); even successful parsing still represents unsafe memory access with high availability risk under attacker control.