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CVE-2026-53077
net/rds: Restrict use of RDS/IB to the initial network namespace
Published 2026-06-24 (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-2026-53077 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 | 7.0.10-1 | Update the kernel and reboot. Fixed in 7.0.10-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.0.10-1 | Update the kernel and reboot. Fixed in 7.0.10-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
Prevent using RDS/IB in network namespaces other than the initial one. The existing RDS/IB code will not work properly in non-initial network namespaces.
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/af_rds.c
net/rds/ib.c
- What this is
- RDS - RELIABLE DATAGRAM SOCKETSMAINTAINERS section matched on net/rds/ · netdev@vger.kernel.org · Supported
- Kernel module
- rds
Check it on the machine
grep -w CONFIG_RDS /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 rdsPrints 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 switch
- CONFIG_RDS
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
- 2026-06-24 (4 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
- 0.12%, higher than 1.7% 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 |
|---|---|---|
| 4.3 | 5.10.258 | 3e7f14cd5a51 |
| 4.3 | 5.15.209 | 3174fc703d08 |
| 4.3 | 6.1.175 | c244b79adffa |
| 4.3 | 6.6.141 | 07035306bf72 |
| 4.3 | 6.12.91 | fb407343c0c1 |
| 4.3 | 6.18.33 | a7494479757d |
| 4.3 | 7.0.10 | b6a54f5e9ce9 |
| 4.3 | 7.1 | ebf71dd4aff4 |
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:LAttack vector, local
- Reachability is through local syscalls: unshare a user/network namespace, create an AF_RDS socket, select RDS/IB with setsockopt, then bind/send and tear down the namespace. A remote peer alone cannot create the stale non-init namespace RDS/IB connection.
- AC:LAttack complexity, low
- The attacker controls the namespace lifetime and socket operations needed to leave an RDS/IB connection with a stale net pointer, and syzbot reproduced the UAF. No hard-to-win race or victim state outside attacker control is required.
- PR:LPrivileges required, low
- AF_RDS socket creation and SO_RDS_TRANSPORT do not require real init-namespace root, and the issue is reachable by an unprivileged local user via user namespaces. This is not an unauthenticated remote path, so low local privileges are required.
- UI:NUser interaction, none
- No victim action is needed after the attacker runs the local namespace and socket sequence. The later RDMA/RDS workqueue access occurs asynchronously in kernel context.
- S:UScope, unchanged
- The vulnerability corrupts/accesses kernel resources within the same kernel security authority. It is not a VM escape, IOMMU bypass, or other cross-authority boundary break.
- C:HConfidentiality impact, high
- The bug is a slab use-after-free read of a freed net_namespace from RDS/IB asynchronous connection handling. Under the required kernel scoring guidance, UAFs are scored as high confidentiality impact because freed object reuse can expose kernel memory.
- I:HIntegrity impact, high
- Although the observed report is a UAF read, use-after-free bugs can generally be shaped through heap reuse into stronger memory corruption primitives. Per the required guidance and uncertainty rule, this warrants high integrity impact.
- A:HAvailability impact, high
- Syzbot reports a KASAN slab-use-after-free in rds_conn_path_drop, and the same stale pointer access can trigger kernel oops/panic or destabilize RDS/RDMA workqueues. Kernel crash availability impact is high.