Bug 2481868 (CVE-2026-45846)

Summary: CVE-2026-45846 kernel: bareudp: fix NULL pointer dereference in bareudp_fill_metadata_dst()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in the bareudp driver of the Linux kernel. This vulnerability allows a local attacker to trigger a NULL pointer dereference in the `bareudp_fill_metadata_dst()` function. This occurs because the function attempts to access a NULL socket when the bareudp device is down, leading to a system crash and a Denial of Service (DoS).
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Description OSIDB Bzimport 2026-05-27 11:01:38 UTC 
In the Linux kernel, the following vulnerability has been resolved:

bareudp: fix NULL pointer dereference in bareudp_fill_metadata_dst()

bareudp_fill_metadata_dst() passes bareudp->sock to
udp_tunnel6_dst_lookup() in the IPv6 path without a NULL check.
The socket is only created in bareudp_open() and NULLed in
bareudp_stop(), so calling this function while the device is down
triggers a NULL dereference via sock->sk.

 BUG: kernel NULL pointer dereference, address: 0000000000000018
 RIP: 0010:udp_tunnel6_dst_lookup (net/ipv6/ip6_udp_tunnel.c:160)
 Call Trace:
  <TASK>
  bareudp_fill_metadata_dst (drivers/net/bareudp.c:532)
  do_execute_actions (net/openvswitch/actions.c:901)
  ovs_execute_actions (net/openvswitch/actions.c:1589)
  ovs_packet_cmd_execute (net/openvswitch/datapath.c:700)
  genl_family_rcv_msg_doit (net/netlink/genetlink.c:1114)
  genl_rcv_msg (net/netlink/genetlink.c:1209)
  netlink_rcv_skb (net/netlink/af_netlink.c:2550)
  </TASK>

Add a NULL check returning -ESHUTDOWN, consistent with the xmit paths
in the same driver.
Comment 1 Keith Grant 2026-05-27 12:19:38 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026052713-CVE-2026-45846-ddca@gregkh/T