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CVE-2026-74377
RDMA/rxe: Copy WQE to local buffer in non-SRQ receive path
Published 2026-08-15 (2 months 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-2026-74377 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 | fixed | 6.1.180-1 | Update the kernel and reboot. Fixed in 6.1.180-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.100-1 | Update the kernel and reboot. Fixed in 6.12.100-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
For non-SRQ QPs, the responder reads WQE fields directly from the shared queue buffer mapped into userspace. This allows a malicious user to modify fields like num_sge or sge entries while the kernel is processing the WQE, leading to out-of-bounds reads in rxe_resp_check_length() and copy_data(). Introduce get_recv_wqe() that validates num_sge and copies the WQE to a kernel-local buffer before processing, matching the approach already used for SRQ WQEs in get_srq_wqe(). The srq_wqe buffer is reused since SRQ and non-SRQ paths are mutually exclusive per QP.
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/rxe/rxe_resp.c
- What this is
- SOFT-ROCE DRIVER (rxe)MAINTAINERS section matched on drivers/infiniband/sw/rxe/ · linux-rdma@vger.kernel.org · Supported
- Kernel module
- rdma_rxe
Check it on the machine
grep -wE 'CONFIG_INFINIBAND|CONFIG_RDMA_RXE' /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 rdma_rxePrints 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, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.
- bookwormMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, i386/686, i386/686-pae, i386/rt/686-pae
- trixieMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp
- forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armhf/armmp, armhf/armmp-lpae
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_INFINIBAND, CONFIG_RDMA_RXE
- 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
- 2026-08-15 (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
- 0.13%, 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 |
|---|---|---|
| 4.8 | 6.1.178 | 2e60378fb3c8 |
| 4.8 | 6.6.145 | fc72fd61cc8b |
| 4.8 | 6.12.97 | 9fa785137303 |
| 4.8 | 6.18.40 | 5420eebf3b3c |
| 4.8 | 7.1.5 | a211b7904aed |
| 4.8 | 7.2 | d6ab440240a0 |
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 mutating mmap'd receive WQEs through /dev/infiniband/uverbs; inbound RoCE packets (rxe_udp_encap_recv→rxe_rcv→rxe_receiver) only trigger processing and cannot alter WQE fields without local control of the userspace-mapped receive queue.
- AC:LAttack complexity, low
- The attacker controls both sides of the TOCTOU—userspace threads racing num_sge/sge edits while posting recv WRs and driving inbound RoCE SEND/WRITE traffic—so out-of-bounds reads in rxe_resp_check_length() and copy_data() are reliably triggerable with retries.
- PR:LPrivileges required, low
- uverbs_devnode() publishes /dev/infiniband/uverbsN as mode 0666, letting any local account create userspace QPs and mmap receive queues; rxe link setup needs CAP_NET_ADMIN obtainable in a user+network namespace via unshare -Urn, matching PR:L kernel guidance.
- UI:NUser interaction, none
- Exploitation is entirely self-driven from the attacker's own RDMA verbs client and concurrent userspace threads; no victim user action, mount, or file open is required.
- S:UScope, unchanged
- Impact is kernel memory corruption and local privilege escalation within the host kernel security authority, not a VM guest-to-host escape, IOMMU/DMA boundary bypass, or other cross-scope compromise.
- C:HConfidentiality impact, high
- Inflating num_sge or rewriting sge entries during processing causes out-of-bounds reads in rxe_resp_check_length() and copy_data() beyond the allocated WQE slot, potentially into adjacent vmalloc/kernel memory, enabling arbitrary kernel information disclosure.
- I:HIntegrity impact, high
- copy_data() walks attacker-forged out-of-bounds sge entries and performs rxe_mr_copy writes of incoming RDMA payload into MR-backed memory; combined with queue overruns this yields controlled memory corruption exploitable for arbitrary write and code execution.
- A:HAvailability impact, high
- Processing a WQE with an attacker-inflated num_sge causes the kernel to walk far past valid sge slots, dereferencing invalid pointers and corrupting memory, reliably producing kernel oops/panic and total loss of availability.