CVE-2011-1780
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 · uneditedThe instruction emulation in Xen 3.0.3 allows local SMP guest users to cause a denial of service (host crash) by replacing the instruction that causes the VM to exit in one thread with a different instruction in a different thread.
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 confidenceThis vulnerability exists in Xen 3.0.3's instruction emulation code for SMP (symmetric multiprocessing) guests. A local user with access to a guest VM can exploit a race condition between threads to replace the instruction that would normally trigger a VM exit with a different instruction via another thread, causing the hypervisor to crash the host system.
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= 3.0.3CVSS 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
- Adjacent
- Complexity
- Low
- Authentication
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- Complete
AV:A/AC:L/Au:N/C:N/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify the installed Xen hypervisor versionRun 'xm info' or 'xl info' and look for the 'xen_version' or 'hypervisor version' field, or check the xen package version with 'rpm -q xen' or 'dpkg -l xen' depending on your OSAffected if The version reported is exactly 3.0.3
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Determine if SMP guests are configured or runningRun 'xm list' or 'xl list' to list all guests, then check the vcpu count for each guest by running 'xm list <guest_name>' or examining the guest configuration file for 'vcpus' settingAffected if Any guest is configured with more than 1 vcpu (SMP guest) or multiple vcpus are currently allocated to running guests
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Verify the host is running the vulnerable Xen 3.0.3 codeCheck the Xen hypervisor build date and version string via 'xl info' or 'dmesg | grep -i xen' output, as the vulnerability exists specifically in the 3.0.3 releaseAffected if The hypervisor is Xen 3.0.3 and cannot confirm a post-2011 stable version is in use
You are affected if your hypervisor is Xen version 3.0.3 and you are hosting or plan to host SMP guests (virtual machines with multiple vcpus) where a local user inside a guest could trigger the race condition in the instruction emulation code.
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 dataUpgrade Xen to a version that includes the fix for this vulnerability (any post-2011 stable release). If immediate patching is not possible, limit local access to VM environments and consider isolating affected guests until the update can be applied.
- Consultation4.0 h
- Implementation6.0 h
- Testing8.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2011-1780 — 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-2011-1780 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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