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CVE-2026-89972
nvme: add missing SRCU grace period in error path
Published 2026-09-16 (33 days ago) by the Linux kernel CNA. Subsystem drivers/nvme. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-89972 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 | vulnerable | 6.1.190-1 | No fix published anywhere yet, neither in Debian nor upstream for the series bookworm tracks. Watch the Debian tracker page for this CVE. Advisories for bookworm have historically landed a median of 23 days after publication. |
| Debian 13trixie | fixedDSA-6568-1 · 2026-10-16 · text | 6.12.113-1 | Update the kernel and reboot. DSA-6568-1 shipped the fix on 2026-10-16, in 6.12.113-1. 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. |
The vulnerability
What the bug is
nvme_alloc_ns() error path at out_unlink_ns removes ns from the namespace head siblings list with list_del_rcu(&ns->siblings) but does not wait for SRCU readers before freeing the namespace struct. Multipath code iterates the head->list under srcu_read_lock() in nvme_find_path() and nvme_mpath_revalidate_paths(), so a concurrent reader can still hold a reference to ns when kfree(ns) runs. The normal removal path in nvme_ns_remove() correctly calls synchronize_srcu(&ns->head->srcu) after list_del_rcu() to wait for in-progress readers. Add the same grace period in the error path.
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
- 2026-09-16 (33 days 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
- 0.64%, higher than 49.4% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- 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 |
|---|---|---|
| 4.15 | 6.12.112 | 0d4735418512 |
| 4.15 | 6.18.51 | d663944dbad8 |
| 4.15 | 7.2.5 | 76023560d60f |
| 4.15 | 7.3 | ef248d5de446 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DSA-6568-1 | 2026-10-16 | trixie 6.12.113-1 | 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:NAttack vector, network
- NVMe host core scans namespaces from NVMe-oF (nvme-tcp/rdma/fc) when a remote target sends NS_CHANGED AENs or Identify data; a malicious or compromised fabric target drives nvme_scan_ns→nvme_alloc_ns and the out_unlink_ns UAF over the network (typically TCP 4420).
- AC:LAttack complexity, low
- The remote target controls both sides of the race: it can stall then fail Identify after list_add_tail_rcu so the new path is on head->list, while concurrent multipath I/O or ANA AENs walk that list under srcu_read_lock in nvme_find_path/nvme_mpath_revalidate_paths; CONFIG_NVME_MULTIPATH is the recommended default.
- PR:NPrivileges required, none
- The attacker is the NVMe-oF peer and needs no host account or capability; NVMe/TCP is unauthenticated by default (TLS and DH-HMAC-CHAP are optional), and AENs plus Identify responses are accepted on an already-established fabrics session.
- UI:NUser interaction, none
- NVMe-oF controllers are persistent boot/autoconnect configuration; namespace rescans, ANA updates, and multipath I/O run from kernel workqueues and the block layer with no further victim action at exploit time.
- S:UScope, unchanged
- The use-after-free corrupts kernel heap (struct nvme_ns) inside the host NVMe driver and does not cross a VM, IOMMU, or other distinct security authority.
- C:HConfidentiality impact, high
- Use-after-free of the namespace object on the multipath siblings list lets an attacker reclaim the kmalloc slab and obtain a kernel read primitive from stale ns->disk/ctrl/flags dereferences in nvme_find_path.
- I:HIntegrity impact, high
- The same UAF is heap-sprayable: multipath I/O and ioctl paths dereference fields of the freed nvme_ns, enabling arbitrary write and control-flow hijacking in kernel context.
- A:HAvailability impact, high
- Any use-after-free of ns during the SRCU list walk can oops or panic the host kernel even without a full exploit, taking down the NVMe storage stack.