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CVE-2026-98257
rds: ib: use rds_conn_drop() on protocol version mismatch
Published 2026-10-06 (13 days ago) by the Linux kernel CNA. Subsystem net/rds. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-98257 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
rds_ib_cm_connect_complete() runs from the RDMA-CM event handler with conn->c_cm_lock held. When the peer negotiates a protocol version older than RDS_PROTOCOL_COMPAT_VERSION, the handler calls rds_conn_destroy(), which is only safe in the rmmod path: it synchronously tears the connection down and flush_work()es the shutdown work cp_down_w. That shutdown work (rds_conn_shutdown()) needs cp_cm_lock, which is the very lock the event handler still holds, so the flush never completes: the two workers wait on each other and the RDS connection workqueues stall for good. All other RDMA-CM failure paths (REJECTED, CONNECT_ERROR, DISCONNECTED) use rds_conn_drop(), which marks the connection RDS_CONN_ERROR and schedules the shutdown work asynchronously. Use it here as well.
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.
net/rds/ib_cm.c
- What this is
- RDS - RELIABLE DATAGRAM SOCKETSMAINTAINERS section matched on net/rds/ · netdev@vger.kernel.org · Supported
- Kernel module
- rds_rdma
Check it on the machine
grep -wE 'CONFIG_RDS|CONFIG_RDS_RDMA' /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 rds_rdmaPrints 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, sidm
- m
- a loadable module on every flavour - check lsmod, can be blacklisted
- Build switches
- CONFIG_RDS, CONFIG_RDS_RDMA
- 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
- 7.5 high
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsource recompute it - Attack vector
- network (AV:N)source
- EPSS
- 0.53%, higher than 43.6% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- net/rds
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 2.6.37 | 5.10.271 | 424019be3f63 |
| 2.6.37 | 5.15.222 | 14fb90067d13 |
| 2.6.37 | 6.1.189 | 344c72a0bc27 |
| 2.6.37 | 6.6.158 | b5c9f2951d33 |
| 2.6.37 | 6.12.112 | d392b16acd09 |
| 2.6.37 | 6.18.54 | 65ca0a503715 |
| 2.6.37 | 7.2.8 | 7d8c22cb2cb1 |
| 2.6.37 | 7.3 | f97d8c7bab78 |
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:NAttack vector, network
- The bad input is dp_protocol_major/minor in the peer's RDMA-CM REP private data, which rds_ib_cm_connect_complete() reads on RDMA_CM_EVENT_ESTABLISHED from rds_rdma_cm_event_handler_cmn(). RDS/IB runs over RoCEv2, whose CM messages travel over routable UDP/IP, so a remote peer supplies the version that hits the rds_conn_destroy() branch.
- AC:LAttack complexity, low
- The attacker produces the active-side state: connect to the RDS listener, then disconnect. IB has no lower-address rule in rds_queue_reconnect(), so the hashed conn reconnects to the attacker, who replies with version 3.0. The deadlock then fires every time.
- PR:NPrivileges required, none
- RDS/IB connection setup has no authentication. rds_ib_cm_handle_connect() only checks the protocol version from the request, and the REP private data the fix concerns is taken from the peer as-is.
- UI:NUser interaction, none
- No local user action is needed. The victim kernel's own reconnect worker (rds_connect_worker via rds_queue_reconnect) starts the outgoing connection after the attacker drops the first one.
- S:UScope, unchanged
- The impact is a deadlock inside the same kernel that processes the RDMA-CM event. No VM, IOMMU or sandbox boundary is crossed.
- C:NConfidentiality impact, none
- rds_conn_destroy() blocks in flush_work(&cp->cp_down_w) before it reaches kmem_cache_free(), so the conn is never freed and then used. No memory is disclosed.
- I:NIntegrity impact, none
- No memory is corrupted. The fault is a lock-ordering deadlock between the CM handler holding c_cm_lock and rds_conn_shutdown() waiting for it, not a write to freed or out-of-bounds memory.
- A:HAvailability impact, high
- The RDMA-CM event worker blocks forever in flush_work() while holding c_cm_lock, and the RDS shutdown work blocks on mutex_lock(&cp->cp_cm_lock). This stalls the RDS connection workqueues and CM event handling for good, and the attacker can repeat it against new connections.