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CVE-2026-89970
nvmet-auth: Synchronize timeout work during SQ teardown
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-2026-89970 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-4841-1 · 2026-10-17 · text | 6.1.190-1 | Update the kernel and reboot. DLA-4841-1 shipped the fix on 2026-10-17, in 6.1.190-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6528-1 · 2026-09-29 · text | 6.12.111-1 | Update the kernel and reboot. DSA-6528-1 shipped the fix on 2026-09-29, in 6.12.111-1. 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. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4817-1 · 2026-10-04 · text | 6.12.111-1~deb12u1 | Update the kernel and reboot. DLA-4817-1 shipped the fix on 2026-10-04, in 6.12.111-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
nvmet_auth_sq_free() cancels auth_expired_work with cancel_delayed_work(). If the work has already started, cancellation does not wait for the callback. Transport teardown can consequently free or reuse the queue containing struct nvmet_sq while nvmet_auth_expired_work() still accesses that SQ. Add a teardown-specific helper that synchronously drains the delayed work before freeing authentication state, and use it from nvmet_sq_destroy(). Keep the non-synchronous helper for in-band authentication state cleanup, where the SQ owner remains alive.
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/target/auth.c
drivers/nvme/target/core.c
drivers/nvme/target/nvmet.h
- What this is
- NVM EXPRESS FABRICS AUTHENTICATIONMAINTAINERS section matched on drivers/nvme/target/auth.c · linux-nvme@lists.infradead.org · Supported
- Kernel module
- nvmet
Check it on the machine
grep -wE 'CONFIG_NVME_TARGET|CONFIG_NVME_TARGET_AUTH' /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 nvmetPrints 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 4 releases, so the answer depends on which release the machine runs.
- bookwormn
- trixie, forky, sid, bookworm · linux-6.12m
- n
- not enabled on any flavour - this release does not build the code
- m
- a loadable module on every flavour - check lsmod, can be blacklisted
- Build switches
- CONFIG_NVME_TARGET, CONFIG_NVME_TARGET_AUTH
- Reads as
- all on means the file is compiled; any one off means it is not.
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
- 0.80%, higher than 55.9% 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 |
|---|---|---|
| 6.0 | 6.1.188 | 664022fa1c93 |
| 6.0 | 6.6.157 | c3c126a6142a |
| 6.0 | 6.12.110 | c17c87bde6d6 |
| 6.0 | 6.18.51 | 7555ddd60af7 |
| 6.0 | 7.2.5 | eb4f9127a2b8 |
| 6.0 | 7.3 | eaa948c0e19b |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4841-1 | 2026-10-17 | bookworm 6.1.190-1 | tracker |
| DLA-4817-1 | 2026-10-04 | bookworm 6.12.111-1~deb12u1 | tracker |
| DSA-6528-1 | 2026-09-29 | trixie 6.12.111-1 | 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
- The UAF is in nvmet-auth timeout work reached via AUTH_SEND on NVMe-oF targets; nvmet-tcp (and nvmet-rdma) accept remote connections, so a network initiator can arm the timer and tear down the queue over TCP/RDMA.
- AC:LAttack complexity, low
- The attacker controls both sides of the race: AUTH_SEND schedules auth_expired_work with an attacker-chosen KATO delay, and closing the connection runs nvmet_sq_destroy(); cancel_delayed_work() does not wait, so the race is repeatable.
- PR:NPrivileges required, none
- AUTH_SEND is dispatched as a Fabrics command before nvmet_check_auth_status() and before DH-HMAC-CHAP credentials are verified; discovery accepts any host NQN, so no Linux privileges or verified secrets are required.
- UI:NUser interaction, none
- No victim user action is required; the attacker connects to an already-deployed NVMe-oF target, sends AUTH_SEND to arm the timeout, and disconnects when the work is due.
- S:UScope, unchanged
- The use-after-free corrupts the in-kernel nvmet_sq/queue object on the target host and does not cross a VM, hypervisor, or IOMMU security boundary.
- C:HConfidentiality impact, high
- Transport teardown can free or reuse the queue containing struct nvmet_sq while nvmet_auth_expired_work() still accesses it; that UAF can be leveraged for kernel information disclosure via heap reuse.
- I:HIntegrity impact, high
- The delayed work writes dhchap_step and dhchap_tid into a potentially freed or reused queue object, giving a kernel UAF write primitive exploitable for memory corruption and control-flow hijacking.
- A:HAvailability impact, high
- Racing the timeout callback against SQ teardown is a kernel UAF of the queue and can oops or panic; the work may also dereference sq->ctrl after teardown has already cleared it.