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Heap-based Buffer OverflowWeakness · CWE-122

CVE-2025-61553

HIGH · 8.2 CVSS v3.1 Published 2025-10-16
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
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
An out-of-bounds write in VirtIO network device emulation in BitVisor from commit 108df6 (2020-05-20) to commit 480907 (2025-07-06) allows local attackers to cause a denial of service (host hypervisor crash) via a crafted PCI configuration space access. Given it's a heap overflow in a privileged hypervisor context, exploitation may enable arbitrary code execution or guest-to-host privilege escalation.

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

An out-of-bounds write vulnerability exists in BitVisor's VirtIO network device emulation due to improper bounds checking when handling PCI configuration space access. The heap overflow occurs when processing crafted PCI configuration space writes, allowing a local attacker to potentially crash the hypervisor (DoS) or achieve arbitrary code execution with hypervisor privileges.

MitigationUpdate BitVisor to a version after commit 480907 which contains the fix. Until then, restrict local guest access and consider network segmentation to limit attack surface.

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

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
Local
Complexity
Low
Privileges
High
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/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 checks

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

  1. Confirm BitVisor is installed
    Check for BitVisor binary or look for BitVisor boot loader on the system (e.g., check /usr/local/lib/bitvisor, /boot/bitvisor, or running processes if applicable)
    Affected if BitVisor hypervisor is not present on the system
  2. Identify BitVisor version
    Run 'bitvisor --version' or check the version string in the BitVisor binary file (e.g., using 'strings' or checking build metadata)
    Affected if Unable to determine version or version predates the fix (commit 480907)
  3. Verify VirtIO network device emulation is in use
    Examine the BitVisor configuration or running VM configuration for VirtIO network (virtio-net) device passthrough or emulation settings
    Affected if VirtIO network device emulation is enabled or passthrough is configured
  4. Check guest VM configurations
    Review VM configuration files or hypervisor settings to identify which guests have VirtIO network devices assigned
    Affected if Any guest VM uses VirtIO network device emulation

If BitVisor is running with VirtIO network device emulation enabled and the version is before the fix (pre-commit 480907), the environment is affected by this vulnerability.

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

Update BitVisor to a version after commit 480907 which contains the fix. Until then, restrict local guest access and consider network segmentation to limit attack surface.

Have this fixed Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing10.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,580
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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-2025-61553 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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