CVE-2026-45846
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NULL pointer dereference in Linux kernel bareudp module

Publication date: 2026-05-27

Last updated on: 2026-06-01

Assigner: kernel.org

Description
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.
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Meta Information
Published
2026-05-27
Last Modified
2026-06-01
Generated
2026-06-16
AI Q&A
2026-05-27
EPSS Evaluated
2026-06-15
NVD
CVE-2026-45846
EUVD
EUVD-2026-32172
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux_kernel linux_kernel *
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Exploitability
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability exists in the Linux kernel's bareudp driver, specifically in the function bareudp_fill_metadata_dst(). The function calls udp_tunnel6_dst_lookup() in the IPv6 path without checking if the socket (bareudp->sock) is NULL. Since the socket is only created in bareudp_open() and set to NULL in bareudp_stop(), calling bareudp_fill_metadata_dst() while the device is down causes a NULL pointer dereference, leading to a kernel crash.

The issue is fixed by adding a NULL check that returns an error code (-ESHUTDOWN) if the socket is NULL, preventing the kernel from dereferencing a NULL pointer.

Impact Analysis

This vulnerability can cause a kernel NULL pointer dereference, which typically results in a kernel crash or system instability. An attacker or a certain sequence of events could trigger this condition, potentially causing denial of service (DoS) by crashing the affected system.

Mitigation Strategies

The vulnerability is caused by a NULL pointer dereference in the bareudp_fill_metadata_dst() function when the device is down. To mitigate this vulnerability, ensure that your Linux kernel is updated to a version where this issue is fixed.

Specifically, apply the patch that adds a NULL check returning -ESHUTDOWN in bareudp_fill_metadata_dst(), consistent with the xmit paths in the same driver.

Until the patch is applied, avoid calling functions that trigger bareudp_fill_metadata_dst() while the device is down to prevent kernel crashes.

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