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CVE-2026-92488
RDMA/erdma: complete object teardown when the destroy command fails
Published 2026-09-17 (31 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-2026-92488 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-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
erdma_destroy_qp(), erdma_destroy_cq(), erdma_dereg_mr(), and erdma_destroy_ah() returned early when erdma_post_cmd_wait() failed, leaking the queue buffers, MTTs, doorbells and the STAG, QPN, CQN and AHN identifiers. A command timeout clears ERDMA_CMDQ_STATE_OK_BIT and permanently disables the command queue, so no retry can succeed; the RDMA core keeps the object after a failed destructor and forced uverbs cleanup then nulls the pointers, making the resources unreachable. Warn on failure but release every software-owned resource and return success, since during terminal destruction the hardware command result is only diagnostic.
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/hw/erdma/erdma_verbs.c
- What this is
- ALIBABA ELASTIC RDMA DRIVERMAINTAINERS section matched on drivers/infiniband/hw/erdma · linux-rdma@vger.kernel.org · Supported
- Kernel module
- none to look for. The file would have gone into erdma, and Debian does not compile it into that module, so finding erdma in lsmod would say nothing about this CVE.
Check it on the machine
grep -wE 'CONFIG_INFINIBAND|CONFIG_INFINIBAND_ERDMA' /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_INFINIBAND_ERDMA
- 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
- 2026-09-17 (31 days ago)source
- CVSS
- 7.0 high
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.15%, higher than 4.2% 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 |
|---|---|---|
| 6.0 | 6.12.110 | 5fcfc988ecf3 |
| 6.0 | 6.18.52 | ce7d205c2646 |
| 6.0 | 7.2.6 | 334145d683ad |
| 6.0 | 7.3 | 652befcba956 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| 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 bug is reached from ib_uverbs_write(IB_USER_VERBS_CMD_DESTROY_QP/DESTROY_CQ/DEREG_MR/DESTROY_AH) or ib_uverbs_ioctl(UVERBS_METHOD_*_DESTROY) on /dev/infiniband/uverbs*, which call uobj_destroy -> ib_destroy_qp_user/ib_destroy_cq_user/ib_dereg_mr_user -> erdma_destroy_*; a remote RoCE/iWARP peer never supplies that destroy command.
- AC:HAttack complexity, high
- erdma_destroy_qp/cq/ah and erdma_dereg_mr only skip teardown when erdma_post_cmd_wait() fails. That wait returns -ETIME after ERDMA_CMDQ_TIMEOUT_MS and then clears ERDMA_CMDQ_STATE_OK_BIT, or -EIO on a hardware syndrome; the SQE is built by the driver from the kernel-owned QPN/CQN/lkey/AHN, so the attacker cannot force that failure.
- PR:LPrivileges required, low
- ib_uverbs_open() only checks rdma_dev_access_netns() and uverbs_devnode() sets mode 0666. erdma_alloc_ucontext() requires CAP_SYS_RAWIO only when ERDMA_DEV_CAP_FLAGS_EXTEND_DB is unset; on extend-doorbell hardware an unprivileged local user can GET_CONTEXT, CREATE_QP/CQ and then hit the failing destructors.
- UI:NUser interaction, none
- The attacker issues DESTROY_* on their own uverbs fd or closes it so ib_uverbs_close() runs uverbs_destroy_ufile_hw(); no other user must mount a filesystem, open a file, or otherwise cooperate.
- S:UScope, unchanged
- A leftover erdma_cq/erdma_qp in cq_xa/qp_xa and a UAF of the associated ib_ucq_object stay inside the host kernel; this is not a KVM/Xen guest-to-host escape or an IOMMU/DMA boundary bypass.
- C:HConfidentiality impact, high
- On command failure erdma_destroy_cq() returns before xa_erase(&dev->cq_xa). __uverbs_cleanup_ufile(RDMA_REMOVE_DRIVER_FAILURE) then nulls uobj->object without ib_destroy_cq_user and frees the ib_ucq_object, so erdma_ceq_completion_handler() -> ib_uverbs_comp_handler() reads the freed cq->uobject.
- I:HIntegrity impact, high
- The same ib_uverbs_comp_handler() then list_add_tail()s onto the freed ev_queue->event_list and ib_ucq_object.comp_list after DRIVER_FAILURE dropped the uobject, a use-after-free write into slab memory that can corrupt a reused object or freelist metadata.
- A:HAvailability impact, high
- The CEQ tasklet UAF in ib_uverbs_comp_handler() can oops; independently, returning before erdma_free_idx()/put_mtt_entries()/dma_free_coherent() leaks STAG/QPN/CQN/AHN IDs and DMA queue buffers, and a cmdq timeout permanently disables further commands.