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XenApplication · Xensource Inc

CVE-2007-4993

MEDIUM · 6.9 CVSS v2.0 Published 2007-09-27
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
74/100
Remediation priority · Elevated
No privileges 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
pygrub (tools/pygrub/src/GrubConf.py) in Xen 3.0.3, when booting a guest domain, allows local users with elevated privileges in the guest domain to execute arbitrary commands in domain 0 via a crafted grub.conf file whose contents are used in exec statements.

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

pygrub's GrubConf.py in Xen 3.0.3 contains a code injection vulnerability where guest domain grub.conf file contents are directly passed to Python exec() statements without sanitization, allowing privileged guest users to escape to domain 0 and execute arbitrary commands on the host.

MitigationUpgrade Xen to a patched version or modify GrubConf.py to remove unsafe exec() usage and implement safe configuration parsing with proper input validation.

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
XenApplication
Affected:= 3.0.3

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
M
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete

AV:L/AC:M/Au:N/C:C/I:C/A:C

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. Identify Xen version
    Run 'xm version' or 'xm info' to determine the installed Xen version
    Affected if Version is exactly 3.0.3
  2. Locate pygrub GrubConf.py
    Find the GrubConf.py file in the pygrub installation - typically in /usr/lib/python*/site-packages/pygrub/ or similar path
    Affected if The file exists and is from Xen 3.0.3
  3. Inspect for unsafe exec() usage
    Open GrubConf.py and search for lines containing 'exec(' that parse grub.conf content without sanitization
    Affected if Code uses exec() to parse guest grub.conf configuration data
  4. Verify paravirtualized guest support
    Check if PV (paravirtualized) guests are configured on the host using 'xm list'
    Affected if PV guests exist and use pygrub as bootloader
  5. Confirm domain 0 exposure
    Verify that pygrub runs in domain 0 context to parse guest grub.conf files
    Affected if pygrub executes in domain 0 and processes untrusted guest configuration files

The environment is affected if running Xen 3.0.3 with pygrub enabled for paravirtualized guests, where guest-provided grub.conf contents are passed to exec() in GrubConf.py within domain 0.

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

Upgrade Xen to a patched version or modify GrubConf.py to remove unsafe exec() usage and implement safe configuration parsing with proper input validation.

Fix this in Xen Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,760
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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-2007-4993 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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