Look up another CVE · open CVE-2026-68417 in the interactive tracker
CVE-2026-68417
RDMA/siw: publish QP after initialization
Published 2026-08-10 (2 months 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-2026-68417 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-4777-1 · 2026-09-08 · text | 6.1.187-1 | Update the kernel and reboot. DLA-4777-1 shipped the fix on 2026-09-08, in 6.1.187-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.101-1 | Update the kernel and reboot. Fixed in 6.12.101-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.6-1 | Update the kernel and reboot. Fixed in 7.1.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.6-1 | Update the kernel and reboot. Fixed in 7.1.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4745-1 · 2026-08-18 · text | 6.12.101-1~deb12u1 | Update the kernel and reboot. DLA-4745-1 shipped the fix on 2026-08-18, in 6.12.101-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
siw_create_qp() currently calls siw_qp_add() before the queues, CQ pointers, state, completion, and device list entry are ready. A QPN lookup can therefore reach a QP that is still being constructed. Move siw_qp_add() to the end of siw_create_qp(), after QP initialization and before adding the QP to the siw device list.
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_verbs.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 5 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, sid, bookworm · linux-6.12n
- 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
- 2026-08-10 (2 months 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
- 0.12%, higher than 1.7% 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 | 5.15.216 | 3c9d12821996 |
| 5.3 | 6.1.183 | 3ff82e3841ec |
| 5.3 | 6.6.148 | 36e91a58397c |
| 5.3 | 6.12.101 | 74912ad168f8 |
| 5.3 | 6.18.42 | fcc9d50022bc |
| 5.3 | 7.1.6 | 52f9fcb19114 |
| 5.3 | 7.2 | bb27fcc67c42 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4777-1 | 2026-09-08 | bookworm 6.1.187-1 | tracker |
| DLA-4745-1 | 2026-08-18 | bookworm 6.12.101-1~deb12u1 | 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
- Exploitation requires local access to the RDMA character devices (/dev/infiniband/uverbsN for create_qp and /dev/infiniband/rdma_cm for the QPN lookup); no network packet reaches the racing code path without a local trigger first.
- AC:LAttack complexity, low
- The attacker controls both sides of the race: one thread issues create_qp while another issues rdma_connect/rdma_accept with an attacker-supplied qp_num, and QPNs from xa_alloc(XA_FLAGS_ALLOC1) are predictable. The post-publish failure can be made deterministic by passing a short udata->outlen, so the window is wide and repeatable at will.
- PR:LPrivileges required, low
- Any unprivileged local user with access to the siw uverbs and rdma_cm character devices can create QPs and issue rdma_connect/rdma_accept with an arbitrary qp_num; no capability check gates siw_create_qp, siw_connect or siw_accept.
- UI:NUser interaction, none
- The attacker drives both the QP creation and the concurrent QPN lookup from its own threads; no action by any other user or administrator is needed.
- S:UScope, unchanged
- The corruption is confined to kernel memory managed by the same kernel security authority; there is no crossing of a VM, IOMMU or sandbox boundary.
- C:HConfidentiality impact, high
- The siw_qp object can be kfree'd by the ib core error path while the CM thread still holds a reference, giving a use-after-free on a slab object the attacker can groom and read back through QP/CM state, enabling disclosure of arbitrary kernel memory.
- I:HIntegrity impact, high
- After the free, siw_free_qp() performs list_del(&qp->devq), vfree() of four pointer fields and siw_put_tx_cpu(qp->tx_cpu) using values read from reallocated attacker-controlled memory, yielding arbitrary-pointer free, list-unlink writes and out-of-range per-CPU decrements suitable for control-flow hijacking.
- A:HAvailability impact, high
- Even without exploitation the race reliably causes kernel crashes: NULL sendq/recvq/scq/rcq dereferences, list_del on an uninitialized devq head, waits on an uninitialized qp_free completion, and use-after-free oopses.