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CVE Record

CVE-2026-45846: bareudp: fix NULL pointer dereference in bareudp_fill_metadata_dst()

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.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2026-45846 is a Linux kernel crash bug in the Bare UDP network driver. If a specific IPv6 metadata path is reached while the Bare UDP device is down, the kernel can dereference a missing socket and fail. The available sources describe denial-of-service impact, not data theft or code execution.

Executive priority

Treat this as a targeted infrastructure stability issue. It is not marked as exploited, but a kernel crash can disrupt affected network hosts. Patch during normal or accelerated kernel maintenance, prioritizing systems using Bare UDP or Open vSwitch.

Technical view

bareudp_fill_metadata_dst() can pass bareudp->sock to udp_tunnel6_dst_lookup() without checking for NULL in the IPv6 path. The socket is created on bareudp_open() and cleared on bareudp_stop(); execution while down can dereference sock->sk. The fix adds a NULL check returning -ESHUTDOWN.

Likely exposure

Exposure is most likely on Linux systems using Bare UDP with IPv6 metadata flows, especially where Open vSwitch can execute actions involving this path. Systems not using Bare UDP or the affected kernel code path are less likely exposed.

Exploitation context

The source bundle does not report active exploitation, and KEV is false. The crash trace shows a reachable kernel path through Open vSwitch and generic netlink, but the provided evidence does not establish remote exploitability, privilege requirements, or public exploit availability.

Researcher notes

The evidence supports a NULL pointer dereference in drivers/net/bareudp.c via the IPv6 lookup path. The affected-version data is coarse and contains upstream kernel versions and commit references, so distro-specific exposure should be validated against vendor kernel backports.

Mitigation direction

  • Update to a Linux kernel containing the referenced stable Bare UDP fix.
  • Prioritize hosts using Bare UDP, IPv6 tunneling, or Open vSwitch datapath actions.
  • Check your distribution vendor advisories for packaged kernel availability.
  • Where patching is delayed, review whether Bare UDP usage can be disabled safely.

Validation and detection

  • Inventory kernel versions and compare them with vendor fixed releases.
  • Check whether Bare UDP devices or modules are present on affected hosts.
  • Identify Open vSwitch deployments that may exercise Bare UDP IPv6 metadata paths.
  • Confirm patched kernels include the NULL check returning -ESHUTDOWN.
Prepared
Confidence
medium
Sources
10

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
9Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux571912c69f0ed731bd1e071ade9dc7ca4aa52065, 571912c69f0ed731bd1e071ade9dc7ca4aa52065, 571912c69f0ed731bd1e071ade9dc7ca4aa52065, 571912c69f0ed731bd1e071ade9dc7ca4aa52065, 571912c69f0ed731bd1e071ade9dc7ca4aa52065, 571912c69f0ed731bd1e071ade9dc7ca4aa52065, 571912c69f0ed731bd1e071ade9dc7ca4aa52065, 571912c69f0ed731bd1e071ade9dc7ca4aa52065unaffected
LinuxLinux5.7, 0, 5.10.258, 5.15.209, 6.1.175, 6.6.141, 6.12.91, 6.18.33, 7.0.10, 7.1affected
Weakness

CWE details

No CWE listed

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