CVE-2017-8420
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 · uneditedSWFTools 2013-04-09-1007 on Windows has a "Data from Faulting Address controls Branch Selection starting at image00000000_00400000+0x0000000000003e71" issue. This issue can be triggered by a malformed TTF file that is mishandled by font2swf. Attackers could exploit this issue for DoS (Access Violation).
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 confidenceSWFTools 2013-04-09-1007 on Windows contains a memory corruption vulnerability in font2swf when processing malformed TTF (TrueType Font) files. The vulnerability involves an indirect branch where data from a faulting address controls branch selection, leading to an access violation 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= 2013-04-09-1007CVSS 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
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/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 SWFTools versionRun 'font2swf -V' or 'swfextract -V' to display version information. On Windows, also check the file properties of font2swf.exe or swfextract.exe by right-clicking the executable and selecting Properties > Details. Look for the version field showing '2013-04-09-1007'.Affected if The version displayed is exactly 2013-04-09-1007 on Windows.
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Verify font2swf executable existsLocate font2swf.exe in the SWFTools installation directory, commonly found at C:\Program Files\SWFTools\ or C:\Program Files (x86)\SWFTools\. Use File Explorer or run 'where font2swf' from Command Prompt.Affected if font2swf.exe is present on the system.
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Identify TTF processing activitySearch for log files, scripts, or batch files that invoke font2swf with TTF input. Run 'font2swf --help' to confirm TTF support. Review any automation or workflows that convert TTF files to SWF.Affected if font2swf is being used to process TrueType Font (TTF) files.
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Check for recent TTF file conversionsReview recent command history, scheduled tasks, or application logs that show font2swf commands with .ttf extensions. Examine any batch files or scripts containing 'font2swf' and '.ttf' together.Affected if TTF files have been recently processed through font2swf.
A user is affected if they have SWFTools version 2013-04-09-1007 installed on Windows and are using font2swf to process TrueType Font files.
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 dataAvoid processing untrusted TTF files with font2swf. If TTF processing is required, validate all font structures before parsing and consider using updated versions or alternative tools with active security maintenance.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-8420 — 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-2017-8420 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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