FreeBSDOperating system
CVE-2020-10565
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 · uneditedgrub2-bhyve, as used in FreeBSD bhyve before revision 525916 2020-02-12, does not validate the address provided as part of a memrw command (read_* or write_*) by a guest through a grub2.cfg file. This allows an untrusted guest to perform arbitrary read or write operations in the context of the grub-bhyve process, resulting in code execution as root on the host OS.
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 confidencegrub2-bhyve fails to validate memory addresses provided in memrw commands (read_*/write_*) passed through grub2.cfg files from a guest VM. This allows a malicious guest to perform arbitrary read/write operations in the context of the grub-bhyve process running as root on the host, enabling code execution with elevated privileges.
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
FreeBSDOperating system
< 525916_2020-02-12CVSS 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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 checksWork through these to decide whether this CVE applies to you.
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Identify the FreeBSD version running on the hostRun 'uname -a' or 'freebsd-version -k' to get the kernel version. Check the build date or version string against the patch date 2020-02-12.Affected if The FreeBSD version is older than the release containing revision 525916 (versions built before February 12, 2020).
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Verify bhyve hypervisor is installedRun 'which bhyve' or 'bhyve --version' to confirm bhyve is present on the system.Affected if bhyve is installed and available on the host.
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Determine the bootloader configured for the VMInspect the VM configuration file or startup command. Look for '-l bootrom=grub2-bhyve' or similar bootloader specification. Alternatively, check if grub-bhyve binary exists with 'which grub-bhyve'.Affected if The VM is configured to use grub2-bhyve (grub-bhyve) as the bootloader rather than UEFI or bhyveload.
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Check if guest can influence grub2.cfg contentsReview the location of the grub2.cfg file used by the VM (typically in /tmp or a guest-defined path). Determine if a malicious guest with write access to this file or the backing storage could modify it.Affected if An untrusted or potentially compromised guest VM has write access to the grub2.cfg file that grub-bhyve reads at boot time.
A system is affected if it runs FreeBSD with bhyve, uses grub2-bhyve as the bootloader, and has a FreeBSD version predating the fix, combined with a guest that can modify the grub2.cfg file consumed by grub-bhyve.
Generated from the published advisory. Verify against your own configuration.
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 data525916_2020-02-12
Update bhyve to a version incorporating the fix from revision 525916 (2020-02-12) or later, which implements proper address validation for memrw commands.
Fix this in FreeBSD
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-10565 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-10565 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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