Bug 2516935 (CVE-2026-74283) - CVE-2026-74283 kernel: tipc: require net admin for TIPCv2 netlink mutators
Summary: CVE-2026-74283 kernel: tipc: require net admin for TIPCv2 netlink mutators
Keywords:
Status: NEW
Alias: CVE-2026-74283
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-08-15 06:41 UTC by OSIDB Bzimport
Modified: 2026-08-20 14:16 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
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Description OSIDB Bzimport 2026-08-15 06:41:15 UTC
In the Linux kernel, the following vulnerability has been resolved:

tipc: require net admin for TIPCv2 netlink mutators

TIPCv2 registers mutating generic-netlink operations without admin
permission flags. Generic netlink only checks CAP_NET_ADMIN when an
operation sets GENL_ADMIN_PERM or GENL_UNS_ADMIN_PERM, so a local
unprivileged process can currently change TIPC state through commands
such as TIPC_NL_NET_SET, TIPC_NL_KEY_SET, TIPC_NL_KEY_FLUSH, and
bearer enable/disable.

The legacy TIPC netlink API already checks netlink_net_capable(...,
CAP_NET_ADMIN) for administrative commands. Give the TIPCv2 mutators
the equivalent generic-netlink gate. Use GENL_UNS_ADMIN_PERM, which
maps to the same namespace-aware CAP_NET_ADMIN check that
netlink_net_capable() performs, so the behaviour matches the legacy
path and keeps working for CAP_NET_ADMIN holders in a non-initial user
namespace (containers).

A QEMU/KASAN repro run as uid/gid 65534 with zero effective
capabilities previously succeeded in changing the network id and node
identity, setting and flushing key material, and enabling/disabling a
UDP bearer. With this patch applied the same operations fail with
-EPERM.


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