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HorndisApplication · Horndis Project

CVE-2020-15137

MEDIUM · 5.9 CVSS v3.1 Published 2020-08-12
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
61/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
All versions of HoRNDIS are affected by an integer overflow in the RNDIS packet parsing routines. A malicious USB device can trigger disclosure of unrelated kernel memory to userspace applications on the host, or can cause the kernel to crash. Kernel memory disclosure is especially likely on 32-bit kernels; 64-bit kernels are more likely to crash on attempted exploitation. It is not believed that kernel memory corruption is possible, or that unattended kernel memory disclosure without the collaboration of a userspace program running on the host is possible. The vulnerability is in `HoRNDIS::receivePacket`. `msg_len`, `data_ofs`, and `data_len` can be controlled by an attached USB device, and a negative value of `data_ofs` can bypass the check for `(data_ofs + data_len + 8) > msg_len`, and subsequently can cause a wild pointer copy in the `mbuf_copyback` call. The software is not maintained and no patches are planned. Users of multi-tenant systems with HoRNDIS installed should only connect trusted USB devices to their system.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Integer overflow in HoRNDIS USB tethering driver's RNDIS packet parsing in function receivePacket allows a malicious USB device to control msg_len, data_ofs, and data_len. A negative data_ofs bypasses a bounds check, leading to wild pointer copy in mbuf_copyback that causes kernel memory disclosure (especially on 32-bit) or kernel crash (on 64-bit).

MitigationSince HoRNDIS is unmaintained with no patches planned, only connect trusted USB devices; consider removing the software if USB tethering is not required, or seek alternative maintained USB networking solutions.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
HorndisApplication
Affected:all versions

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Physical
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

CVSS:3.1/AV:P/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check if HoRNDIS kernel extension is loaded
    Run 'kextstat | grep -i horndis' or 'kextstat | grep com.apple.driver.AppleUSBRNDIS' in Terminal to see if the HoRNDIS kext is currently loaded in memory
    Affected if The kernel extension appears in the output, meaning HoRNDIS is active
  2. Verify HoRNDIS is installed on the system
    Check for HoRNDIS files: run 'ls /Library/Extensions/' and look for 'HoRNDIS.kext' or search with 'find /Library -name "*HoRNDIS*" -o -name "*horndis*"'
    Affected if The HoRNDIS.kext or related files are found in the system extensions directory
  3. Identify HoRNDIS version if possible
    Run 'defaults read /Library/Extensions/HoRNDIS.kext/Contents/Info CFBundleVersion' or check the kext's Info.plist for version information
    Affected if Any version number is returned - note that all versions of HoRNDIS are affected
  4. Check for active USB RNDIS device connections
    Run 'ioreg -l | grep -i RNDIS' or check System Information > USB for connected devices that may be using the RNDIS protocol
    Affected if A USB device with RNDIS networking capability is connected while HoRNDIS is loaded
  5. Review system logs for HoRNDIS activity
    Run 'log show --predicate " subsystem == 'com.apple.driver.AppleUSBRNDIS' " --last 1h' to check recent kernel logs for HoRNDIS driver activity
    Affected if Logs show HoRNDIS driver loaded and processing USB device connections

If HoRNDIS.kext is loaded in the kernel and a USB device with RNDIS capability is or can be connected, the system is vulnerable to CVE-2020-15137 - since all HoRNDIS versions are affected, presence and active use of this driver is the sole condition for exposure.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Since HoRNDIS is unmaintained with no patches planned, only connect trusted USB devices; consider removing the software if USB tethering is not required, or seek alternative maintained USB networking solutions.

Fix this in Horndis Scoped from the published advisory
  • Consultation2.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,100
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-15137 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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