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CVE-2026-98367
RDMA/siw: Clear association under lock if siw_qp_modify fails in siw_accept
Published 2026-10-06 (13 days ago) by the Linux kernel CNA. Subsystem drivers/infiniband. Debian urgency: not yet assigned.
Debian does not build this code. The per-release build detail is under "Where it lives" below.
What to do, per Debian release
Debian's own status for CVE-2026-98367 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-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 | 7.2.8-1 | Update the kernel and reboot. Fixed in 7.2.8-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.8-1 | Update the kernel and reboot. Fixed in 7.2.8-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
We need to clear cep before release state_lock as siw_qp_llp_close and siw_qp_modify->siw_qp_llp_close did. Otherwise if siw_qp_modify() fails in siw_accept(), the QP's state_lock is released before the error path cleanup. A concurrent ibv_modify_qp() transitioning the QP to ERROR can race in this window: siw_accept() ibv_modify_qp(ERROR) ---------------------- ---------------------- siw_qp_modify() fails up_write(&qp->state_lock) down_write(&qp->state_lock) nextstate_from_idle(): if (qp->cep) siw_cep_put(qp->cep) <- frees cep qp->cep = NULL goto error cep->qp = NULL <- UAF Clear qp->cep and drop the association reference taken by siw_cep_get(), all under the write lock held from the initial down_write(&qp->state_lock). Thread B therefore sees qp->cep == NULL, skips its own put, and cannot free the cep before siw_accept() is done with it.
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/infiniband/sw/siw/siw_cm.c
- What this is
- SOFT-IWARP DRIVER (siw)MAINTAINERS section matched on drivers/infiniband/sw/siw/ · linux-rdma@vger.kernel.org · Supported
- Kernel module
- none to look for. The file would have gone into siw, and Debian does not compile it into that module, so finding siw in lsmod would say nothing about this CVE.
Check it on the machine
grep -wE 'CONFIG_INFINIBAND|CONFIG_RDMA_SIW' /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.
Show whether Debian builds this, per release
Debian does not build this code. In 4 releases below, every kernel flavour Debian publishes has the switch off, so the vulnerable file is compiled into no kernel binary Debian ships.
- bookworm, trixie, forky, sidn
- n
- not enabled on any flavour - this release does not build the code
- Build switches
- CONFIG_INFINIBAND, CONFIG_RDMA_SIW
- 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
- 2026-10-06 (13 days 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 2.3% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/infiniband
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.3 | 5.10.271 | f11e09fe2fc3 |
| 5.3 | 5.15.222 | e3f039082856 |
| 5.3 | 6.1.189 | ad50d19f3d1c |
| 5.3 | 6.6.158 | 030306bbb927 |
| 5.3 | 6.12.112 | df2584750314 |
| 5.3 | 6.18.54 | 9dcc0f4e488b |
| 5.3 | 7.2.8 | bfdc744bf20a |
| 5.3 | 7.3 | 32cd87f54dd1 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4841-1 | 2026-10-17 | bookworm 6.1.190-1 | tracker |
| 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:LAttack vector, local
- siw_accept() is called through the ops.iw_accept hook from iw_cm_accept(), which a local process reaches with the RDMA_USER_CM_CMD_ACCEPT command on /dev/infiniband/rdma_cm. The racing side is the uverbs MODIFY_QP command (ibv_modify_qp to ERROR), also local. No wire message carries data that causes the siw_qp_modify() failure, so the attack is local.
- AC:LAttack complexity, low
- The attacker does control both racing threads, since it owns the QP and issues the accept and modify_qp calls itself. Even so, AC is High: in siw_accept the only way siw_qp_modify() can fail is siw_qp_readq_init() hitting a vcalloc() ENOMEM, and IRD/ORD are capped at 128, so the allocations are small. That failure depends on system-wide memory exhaustion, which the attacker cannot produce on demand.
- PR:LPrivileges required, low
- Running rdma_accept and ibv_modify_qp on a QP the user created on an existing siw device needs only ordinary access to the rdma_cm and uverbs device nodes. Creating the siw link through RDMA_NLDEV_CMD_NEWLINK is admin-only, but no privilege is needed to use a device that already exists.
- UI:NUser interaction, none
- The attacker drives both siw_accept() and the concurrent ibv_modify_qp(ERROR) through their own rdma_cm and verbs calls, and the connecting peer can be the attacker over loopback. No other user has to do anything.
- S:UScope, unchanged
- The freed siw_cep and the writes into it both stay inside the kernel's own security authority. No VM, IOMMU or sandbox boundary is crossed.
- C:HConfidentiality impact, high
- siw_qp_nextstate_from_idle() frees the siw_cep by calling siw_cep_put(qp->cep). The error path in siw_accept() then keeps using that freed object: it writes cep->qp = NULL, runs siw_free_cm_id, and calls siw_cep_set_free_and_put. A reclaimed object in that slot gives the attacker a use-after-free primitive that can be built into a kernel memory leak.
- I:HIntegrity impact, high
- After the free, the error path writes cep->qp = NULL and does kref and lock operations on the dead siw_cep. That corrupts whatever object has taken over the slot, and this kind of UAF write can be used to corrupt kernel data or hijack control flow.
- A:HAvailability impact, high
- A kref_put or lock operation on the freed siw_cep in siw_cep_set_free_and_put can corrupt the slab or oops the kernel, and that crashes the host.