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CVE-2026-92507
RDMA/core: Fix potential use after free in ib_dealloc_pd_user()
Published 2026-09-17 (31 days ago) by the Linux kernel CNA. Subsystem drivers/infiniband. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-92507 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
When accessing a PD via the netlink path the only synchronization mechanism for the said PD is rdma_restrack_get(). Currently, rdma_restrack_del() is invoked at the end of ib_dealloc_pd_user(), which is too late, since by that point vendor-specific resources associated with the PD might already be freed. This can leave a short window where the PD remains accessible through restrack, leading to a potential use-after-free. Fix this by moving the rdma_restrack_begin_del() call to the start of ib_dealloc_pd_user(), ensuring that the PD is removed from restrack before its internal resources are released. This guarantees that no new users hold references to a PD that is in the process of destruction. In addition, this change preserves the intended inverted order between create and destroy routines: resources are added to restrack at the end of successful creation, and hence shall be removed from the restrack first thing during the destruction flow, which keeps the lifecycle management consistent and predictable.
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/core/verbs.c
- What this is
- INFINIBAND SUBSYSTEMMAINTAINERS section matched on drivers/infiniband/ · linux-rdma@vger.kernel.org · Supported
- Kernel module
- ib_core
Check it on the machine
grep -w CONFIG_INFINIBAND /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 ib_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 as a loadable module. Every release below compiles it as a module on every flavour, so whether the code is in the running kernel depends on whether that module is loaded.
- bookworm, trixie, forky, sid, bookworm · linux-6.12m
- m
- a loadable module on every flavour - check lsmod, can be blacklisted
- Build switch
- CONFIG_INFINIBAND
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
- 2026-09-17 (31 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
- 0.16%, higher than 5.2% 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 |
|---|---|---|
| 5.10 | 6.1.188 | df0e9efe61ca |
| 5.10 | 6.6.157 | 7647363fa020 |
| 5.10 | 6.12.110 | d9c0daf9362a |
| 5.10 | 6.18.52 | 66d65f36d397 |
| 5.10 | 7.2.6 | c06f2856a1d7 |
| 5.10 | 7.3 | 8b90e7013422 |
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:LAttack vector, local
- The race is between ib_uverbs_dealloc_pd()/uverbs_free_pd() (IB_USER_VERBS_CMD_DEALLOC_PD or UVERBS_METHOD_PD_DESTROY on /dev/infiniband/uverbs*) and nldev_res_get_pd_dumpit()/nldev_res_get_pd_doit() via NETLINK_RDMA RDMA_NLDEV_CMD_RES_PD_GET. Those syscalls supply the destroy and the dump; no remote protocol message carries the malformed state.
- AC:LAttack complexity, low
- The attacker runs both sides: one thread deallocates its PD while another loops RDMA_NLDEV_CMD_RES_PD_GET. res_get_common_dumpit() can rdma_restrack_get() until rdma_restrack_del(), and ops.dealloc_pd() (often a firmware round-trip) sits in that window, so the attacker creates and retries the race.
- PR:LPrivileges required, low
- uverbs_devnode() sets /dev/infiniband/uverbs* to 0666, so an unprivileged process can alloc/dealloc a PD. RDMA_NLDEV_CMD_RES_PD_GET has no RDMA_NL_ADMIN_PERM, and NETLINK_RDMA is created with NL_CFG_F_NONROOT_RECV, so sendmsg to kernel portid 0 does not need CAP_NET_ADMIN.
- UI:NUser interaction, none
- The attacker opens uverbs, allocates a PD, then concurrently issues IB_USER_VERBS_CMD_DEALLOC_PD and RDMA_NLDEV_CMD_RES_PD_GET; no other user action is required.
- S:UScope, unchanged
- A successful UAF corrupts memory in ib_core and the RDMA driver on the same host kernel. It does not cross a VM, IOMMU, or other security-authority boundary.
- C:HConfidentiality impact, high
- ib_dealloc_pd_user() runs dereg_mr(pd->__internal_mr) and ops.dealloc_pd() before rdma_restrack_del(). fill_res_pd_entry() can still rdma_restrack_get() that PD and read pd, including pd->uobject->context. In that window bnxt_re_dealloc_pd() kfree()s fence->mr via bnxt_re_destroy_fence_mr(), so reused driver objects can disclose kernel memory.
- I:HIntegrity impact, high
- The same window lets the attacker spray and reuse objects freed inside ops.dealloc_pd() (bnxt_re_destroy_fence_mr() kfree(mr), rxe_cleanup() of the PD pool element) while fill_res_pd_entry() still holds the PD via restrack, which is a kernel write/control-flow hijack primitive.
- A:HAvailability impact, high
- Racing nldev_res_get_pd_dumpit() against ib_dealloc_pd_user() after vendor teardown can oops in fill_res_pd_entry() while it follows pd->uobject->context on a PD whose driver state is already gone, crashing the host.