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CVE-2026-53355
net: rds: clear i_sends on setup unwind
Published 2026-07-01 (4 months 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-2026-53355 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-4665-1 · 2026-07-03 · text | 6.1.176-1 | Update the kernel and reboot. DLA-4665-1 shipped the fix on 2026-07-03, in 6.1.176-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.94-1 | Update the kernel and reboot. Fixed in 6.12.94-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.0.13-1 | Update the kernel and reboot. Fixed in 7.0.13-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.0.13-1 | Update the kernel and reboot. Fixed in 7.0.13-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
The RDS IB connection teardown path is written so it can run during partial startup and on repeated shutdown attempts. It uses NULL pointers to distinguish resources that are still owned from resources that have already been released. When rds_ib_setup_qp() fails after allocating i_sends but before allocating i_recvs, the sends_out path frees i_sends without clearing the pointer. A later shutdown pass can still treat that stale pointer as a live send ring allocation. Clear i_sends after vfree() in the error unwind path so the existing shutdown logic continues to use the correct ownership state.
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
- 2026-07-01 (4 months ago)source
- CVSS
- 9.8 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- network (AV:N)source
- EPSS
- 0.42%, higher than 35.0% 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 |
|---|---|---|
| 4.11 | 5.10.259 | 66cccec11142 |
| 4.11 | 5.15.210 | 2c5e5e4a5970 |
| 4.11 | 6.1.176 | 29d940026dce |
| 4.11 | 6.6.143 | e7cf30aa5f1f |
| 4.11 | 6.12.94 | f16ad421a4e3 |
| 4.11 | 6.18.36 | 1d4ec754ee38 |
| 4.11 | 7.0.13 | 27040bbca289 |
| 4.11 | 7.1 | 20cf0fb715c4 |
| 3.18.74 | 0 | 0 |
| 4.1.46 | 0 | 0 |
| 4.4.91 | 0 | 0 |
| 4.9.54 | 0 | 0 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4671-1 | 2026-07-05 | bullseye 6.1.176-1~deb11u1 | tracker |
| DLA-4665-1 | 2026-07-03 | bookworm 6.1.176-1 | tracker |
| DLA-4664-1 | 2026-07-03 | bullseye 5.10.259-1 | 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 vulnerable RDS/IB setup path is reachable by a remote RDMA/RDS peer through RDMA CM connection requests handled by the kernel listener, before any RDS-level authentication. It is also reachable locally via AF_RDS send-triggered connects, but the remote network path is the higher-severity reasonable scenario.
- AC:LAttack complexity, low
- The bug is triggered when `i_recvs` allocation fails after `i_sends` was allocated, and an attacker can drive repeated connection setup/resource pressure to reach that condition. No race or victim-controlled timing is required.
- PR:NPrivileges required, none
- The incoming RDMA CM connect path requires no local account or authenticated RDS credentials. Local AF_RDS access is unprivileged in the initial network namespace, but the remote path makes privileges none.
- UI:NUser interaction, none
- No victim user action is needed once the RDS/IB listener is present. Connection setup and teardown are handled by kernel workqueues/CM callbacks.
- S:UScope, unchanged
- The corruption occurs inside the host kernel RDS/IB connection state and does not cross a separate security authority such as a guest-host or IOMMU boundary. This is standard kernel compromise/DoS scope.
- C:HConfidentiality impact, high
- The stale `i_sends` pointer creates a use-after-free/double-free of kernel memory and the teardown path reads the freed send ring. Under the required high-severity assumption for UAF-style memory corruption, this can support kernel memory disclosure.
- I:HIntegrity impact, high
- The same stale-pointer/double-free condition can corrupt kernel allocator state or operate on attacker-reused freed memory. As kernel memory corruption, it is defensibly scored as capable of arbitrary write/control-flow impact.
- A:HAvailability impact, high
- At minimum, the later shutdown pass can dereference and free an already freed kernel allocation, causing an oops, panic, or allocator corruption. Repeated unauthenticated connection attempts can therefore crash or destabilize the kernel.