Debian LinuxOperating system · Debian
CVE-2016-9602
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 · uneditedQemu before version 2.9 is vulnerable to an improper link following when built with the VirtFS. A privileged user inside guest could use this flaw to access host file system beyond the shared folder and potentially escalating their privileges on a host.
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 confidenceQEMU before version 2.9 contains a path traversal vulnerability in VirtFS (9pfs) where improper link following allows a privileged guest user to escape the intended shared folder boundary and access host filesystem directories outside the designated share, potentially enabling host privilege escalation.
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
Debian LinuxOperating system
= 8.0< 2.9CVSS 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
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:N/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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Check installed QEMU versionRun 'qemu-system-x86_64 --version' or 'qemu-img --version' to determine the QEMU version numberAffected if Version is less than 2.9 (e.g., 2.8.x, 2.7.x, etc.)
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Verify VirtFS/9pfs support is presentCheck if the qemu-system binary includes 9pfs support: 'qemu-system-x86_64 -net nic,model=virtio -fsdev help 2>&1 | grep -i 9p' or review QEMU build configurationAffected if 9pfs filesystem driver is available in the QEMU binary
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Identify VMs using VirtFS shared foldersExamine VM configuration files (e.g., in /etc/libvirt/qemu/ for libvirt, or look for -fsdev or 9p mount options in VM launch commands) for entries containing 'fsdev=*,type=9p' or 'mount_tag='Affected if Any VM configuration shows VirtFS/9pfs shared folder exports with host_path defined
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Confirm guest has elevated privilegesReview VM configuration to determine if the guest operating system runs with elevated privileges (root/Administrator) or if the 9p share is exposed to privileged guest processesAffected if Guest OS runs as privileged user or the shared folder is accessible to privileged guest processes
User is affected if running QEMU version below 2.9 with at least one VirtFS (9pfs) shared folder configured and accessible to a privileged guest user, allowing path traversal outside the intended share boundary.
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 data2.9
Upgrade QEMU to version 2.9 or later; if immediate upgrade is not feasible, disable VirtFS for untrusted guests and apply vendor-provided security patches.
Fix this in Debian Linux
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-9602 — 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-2016-9602 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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