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CVE Record

CVE-2018-8043: The unimac_mdio_probe function in drivers/net/phy/mdio-bcm-unimac.c in the Linux kernel through 4.15.8 does...

The unimac_mdio_probe function in drivers/net/phy/mdio-bcm-unimac.c in the Linux kernel through 4.15.8 does not validate certain resource availability, which allows local users to cause a denial of service (NULL pointer dereference).

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel availability bug. On affected systems, a local user could trigger a NULL pointer dereference in the Broadcom UniMAC MDIO driver path and cause a denial of service. The public bundle does not show remote exploitation, privilege escalation, CVSS scoring, or CISA KEV listing.

Executive priority

Patch during normal kernel maintenance unless the affected systems are shared, exposed to untrusted local users, or have strict availability requirements. No evidence in the bundle supports emergency internet-wide exploitation response.

Technical view

CVE-2018-8043 affects the Linux kernel through 4.15.8 in unimac_mdio_probe within drivers/net/phy/mdio-bcm-unimac.c. The issue is missing validation of resource availability, leading to a NULL pointer dereference. The referenced upstream Linux commit and Ubuntu advisories indicate patched kernel updates exist, but affected distro package ranges are not fully enumerated here.

Likely exposure

Likely exposure is Linux systems running kernels through 4.15.8 where the Broadcom UniMAC MDIO driver is present or enabled. Exposure depends on distribution backports and vendor kernel packaging. Ubuntu advisories are cited, but the bundle does not provide a complete affected product matrix.

Exploitation context

Sources describe local-user denial of service only. CISA KEV is false in the bundle, and no cited source states active exploitation. Treat risk as higher on shared, multi-user, appliance, or embedded Linux systems where local access is plausible and uptime matters.

Researcher notes

The core weakness is a missing resource-availability check in a kernel probe function. Public evidence supports local denial of service via NULL pointer dereference. The bundle lacks CVSS, CWE, complete affected package details, and any confirmation of exploitation in the wild.

Mitigation direction

  • Apply vendor kernel updates referenced by your Linux distribution.
  • Verify the kernel includes upstream commit 297a6961ffb8ff4dc66c9fbf53b924bd1dda05d5.
  • Prioritize shared or uptime-sensitive systems with local user access.
  • Check Ubuntu USN guidance if running affected Ubuntu kernel packages.
  • Use vendor advisories for exact package names and reboot requirements.

Validation and detection

  • Inventory Linux kernels at or before 4.15.8.
  • Check whether the Broadcom UniMAC MDIO driver is built, loaded, or packaged.
  • Compare installed kernel packages against Ubuntu or vendor advisories.
  • Confirm the running kernel is the patched version after reboot.
  • Review local account access on systems that cannot be patched quickly.
Prepared
Confidence
medium
Sources
8

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

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2018-8043 mapping review

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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
0Timeline events
0ADP providers
7Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

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