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Fencer Vulns
no cvss —

CVE-2026-97476 json

rds: filter RDS_INFO_* getsockopt by caller's netns

published 2026-09-24 45 d ago modified 2026-10-03 36 d ago also EUVD-2026-86074

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 6%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

rds: filter RDS_INFO_* getsockopt by caller's netns

The RDS_INFO_* family of getsockopt(2) options reads several file-scope global lists that are not per-netns:

rds_sock_info / rds6_sock_info, rds_sock_inc_info / rds6_sock_inc_info -> rds_sock_list rds_tcp_tc_info / rds6_tcp_tc_info -> rds_tcp_tc_list rds_conn_info / rds6_conn_info, rds_conn_message_info_cmn (for the *_SEND_MESSAGES and *_RETRANS_MESSAGES variants), rds_for_each_conn_info (for RDS_INFO_IB_CONNECTIONS) -> rds_conn_hash[]

The handlers do not filter by the caller's network namespace. rds_info_getsockopt() has no netns or capable() check, and rds_create() has no capable() check, so AF_RDS is reachable from an unprivileged user namespace. As a result, an unprivileged caller in a fresh user_ns plus netns can read the bound address and sock inode of every RDS socket on the host, the peer address of incoming messages on every RDS socket on the host, the peer address and TCP sequence numbers of every rds-tcp connection on the host, and the peer address and RDS sequence numbers of every RDS connection on the host.

The rds-tcp transport is reachable from a non-initial netns (see rds_set_transport()), so a one-shot init_net gate at rds_info_getsockopt() would deny legitimate per-netns visibility to rds-tcp callers. Instead, filter at each handler by comparing the netns of the caller's socket to the netns of the list entry, or to rds_conn_net(conn) for connection paths. Only copy entries whose netns matches the caller. Counters (RDS_INFO_COUNTERS) are aggregate statistics and remain global.

Reproducer (KASAN VM, rds and rds_tcp loaded): an AF_RDS socket binds 127.0.0.1:4242 in init_net as root. A child process enters a fresh user_ns plus netns and opens AF_RDS there, then calls getsockopt(SOL_RDS, RDS_INFO_SOCKETS). Before this change, the child sees the init_net socket. After this change, the child sees zero entries.

Drop the rds_sock_count, rds_tcp_tc_count, and rds6_tcp_tc_count globals. v2 used them for the size precheck and lens->nr; v3 replaced the precheck with a per-ns count from a first pass over the list, so the globals have no remaining readers. The matching increments and decrements in rds_create()/rds_destroy_sock() and rds_tcp_set_callbacks()/rds_tcp_restore_callbacks() go away with them. Reported by the kernel test robot under clang W=1.

Patch / fix

  • Linux Linux 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53, 7.2
  • linux Debian 12 6.1.190-1
  • linux Debian 13 6.12.111-1
  • linux Debian 14 7.2.6-1
  • linux-6.12 Debian 12 6.12.111-1~deb12u1

debian advisories DEBIAN-CVE-2026-97476

  • linux Ubuntu 22.04 LTS 5.15.0-202.212
  • linux Ubuntu 26.04 LTS 7.0.0-42.42
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1119.126
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1120.130
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1115.121
  • linux-ibm Ubuntu 22.04 LTS 5.15.0-1113.117

ubuntu advisories UBUNTU-CVE-2026-97476

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel Azure Linux 3.0 6.6.158.1-1

azure linux advisories AZL-103778

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-97476 updated cvss 7.0

kernel: rds: filter RDS_INFO_* getsockopt by caller's netns

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.17% chance of exploitation in the next 30 days, higher than 6% of all scored CVEs (FIRST EPSS, 2026-11-08).

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.