CVE-2006-5646
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 · uneditedHeap-based buffer overflow in Sophos Anti-Virus and Endpoint Security before 6.0.5, Anti-Virus for Linux before 5.0.10, and other platforms before 4.11, when archive scanning is enabled, allows remote attackers to trigger a denial of service (memory corruption) via a CHM file with an LZX decompression header that specifies a Window_size of 0.
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 confidenceHeap-based buffer overflow in Sophos Anti-Virus and Endpoint Security products when archive scanning is enabled. The vulnerability is triggered by specially crafted CHM files containing an LZX decompression header that specifies a Window_size of 0, causing memory corruption and denial of service.
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= 4.04= 4.05= 4.5.3= 4.5.4= 4.5.11= 4.5.12= 4.7.1= 4.7.2= 5.0.1= 5.0.2= 5.0.4= 5.1<= 6.04CVSS 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
- Authentication
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- Partial
AV:N/AC:L/Au:N/C:N/I:N/A:P
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 Sophos product and versionRun 'sophos --version' or check the installed package via system package manager (rpm -qi sophos-antivirus or dpkg -l sophos*)Affected if The installed version is one of: 4.04, 4.05, 4.5.3, 4.5.4, 4.5.11, 4.5.12, 4.7.1, 4.7.2, 5.0.1, 5.0.2, 5.0.4, 5.1 for Anti-Virus, or 6.04 or earlier for Endpoint Security
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Confirm Sophos Endpoint Security versionCheck installed version via Windows Add/Remove Programs, or run 'Savesoft.exe /version' if available, or check the installed directory for version metadataAffected if The installed version is 6.04 or earlier
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Verify archive scanning configurationCheck Sophos configuration settings - on Windows check the on-access or on-demand scan policy for archive scanning; on Linux check /etc/sophos/sav.cfg or run 'savconfig query' for archive scanning flagsAffected if Archive scanning (also called archive, compressed, or container file scanning) is enabled in the active scan policy
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Check CHM file handling in scan settingsVerify that CHM (Compiled HTML Help) files are included in the archive scanning scope - review the file extension list in the scan configuration for archive typesAffected if CHM files are being scanned as part of archive scanning (this is typically the default behavior when archive scanning is enabled)
You are affected if you have a vulnerable Sophos version (Anti-Virus 4.04-5.1 or Endpoint Security <=6.04) AND archive scanning is enabled for CHM files, as the vulnerability triggers during LZX decompression of malformed CHM archives.
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 dataUpdate Sophos Anti-Virus and Endpoint Security to version 6.0.5 or later (Linux to 5.0.10 or later, other platforms to 4.11 or later). Disable archive scanning for CHM files as a temporary workaround if immediate patching is not feasible.
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 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 $3,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2006-5646 — 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-2006-5646 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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