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CVE Record

CVE-2026-23140: bpf, test_run: Subtract size of xdp_frame from allowed metadata size

In the Linux kernel, the following vulnerability has been resolved: bpf, test_run: Subtract size of xdp_frame from allowed metadata size The xdp_frame structure takes up part of the XDP frame headroom, limiting the size of the metadata. However, in bpf_test_run, we don't take this into account, which makes it possible for userspace to supply a metadata size that is too large (taking up the entire headroom). If userspace supplies such a large metadata size in live packet mode, the xdp_update_frame_from_buff() call in xdp_test_run_init_page() call will fail, after which packet transmission proceeds with an uninitialised frame structure, leading to the usual Bad Stuff. The commit in the Fixes tag fixed a related bug where the second check in xdp_update_frame_from_buff() could fail, but did not add any additional constraints on the metadata size. Complete the fix by adding an additional check on the metadata size. Reorder the checks slightly to make the logic clearer and add a comment.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2026-23140 is a Linux kernel flaw in BPF XDP test-run handling. A user-supplied metadata size can be accepted even though it leaves no room for required frame data, causing packet transmission to continue with an uninitialized frame structure. Business risk depends on where affected kernels and BPF test-run capability are available.

Executive priority

Treat as a kernel maintenance priority for Linux fleets, especially multi-user, CI, development, or packet-processing systems. Escalate once vendor severity or exploitability details are available; current evidence does not support emergency active-exploitation handling.

Technical view

In bpf_test_run live packet mode, XDP frame headroom accounting omitted struct xdp_frame size when validating metadata. Oversized metadata can make xdp_update_frame_from_buff() fail in xdp_test_run_init_page(), while transmission continues with an uninitialized frame. Stable fixes add metadata-size validation and clarify the checks.

Likely exposure

Exposure is limited to Linux systems running affected kernel versions where userspace can exercise BPF test_run live packet mode. The source bundle lists Linux as affected but provides no distribution advisories, package names, or deployment prevalence.

Exploitation context

The provided sources do not report active exploitation, public exploit code, or KEV listing. The vulnerability appears locally reachable through kernel BPF test-run behavior, but exact privilege requirements and practical impact are not stated in the bundle.

Researcher notes

The key defect is metadata headroom validation in bpf_test_run for XDP live packet mode. Sources state the failure path leaves an uninitialized frame structure in use, but do not define the resulting impact class, exploitability, or privilege boundary.

Mitigation direction

  • Identify Linux hosts running kernels in the affected ranges listed by the CVE record.
  • Apply vendor or upstream stable kernel updates containing the referenced fixes.
  • Check distribution security advisories for backported fixes and package-specific kernel versions.
  • Limit BPF access to trusted users where operationally possible until patched.

Validation and detection

  • Inventory kernel versions across servers, workstations, containers hosts, and appliances.
  • Map installed kernels to distribution advisories or the referenced upstream stable commits.
  • Review whether untrusted local users can access BPF test-run functionality.
  • Confirm updated kernels are booted, not merely installed.
Prepared
Confidence
medium
Sources
7

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
6Source 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
LinuxLinuxb6f1f780b3932ae497ed85e79bc8a1e513883624, b6f1f780b3932ae497ed85e79bc8a1e513883624, b6f1f780b3932ae497ed85e79bc8a1e513883624, b6f1f780b3932ae497ed85e79bc8a1e513883624, b6f1f780b3932ae497ed85e79bc8a1e513883624unaffected
LinuxLinux5.18, 0, 6.1.161, 6.6.121, 6.12.66, 6.18.6, 6.19affected
Weakness

CWE details

No CWE listed

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