CVE-2017-16796
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 · uneditedIn SWFTools 0.9.2, the png_load function in lib/png.c does not check the return value of a realloc call, which allows remote attackers to cause a denial of service (invalid write and application crash) or possibly have unspecified other impact via vectors involving an IDAT tag in a crafted PNG file.
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 confidenceThe png_load function in lib/png.c of SWFTools 0.9.2 fails to validate the return value from realloc(). When realloc fails and returns NULL, the code continues to use the NULL pointer, causing an invalid write and subsequent application crash. Attackers can exploit this by embedding malicious data in the IDAT chunk of a crafted PNG file.
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= 0.9.2CVSS 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
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/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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Identify installed SWFTools versionRun `swftools -V` or check the package manager for the installed swftools package versionAffected if The version displayed is exactly 0.9.2
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Locate the vulnerable png.c source fileSearch for lib/png.c in the SWFTools source or installation directoryAffected if The file exists and belongs to SWFTools 0.9.2
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Verify the vulnerable code pattern in png_load functionInspect the png_load function in lib/png.c and look for realloc() calls without NULL return value validationAffected if The code shows a realloc() call whose return value is used without checking for NULL first
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Confirm PNG processing capability is in useDetermine if SWFTools is being used to process PNG files or convert them to SWF formatAffected if The environment processes PNG files using swftools utilities such as png2swf
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Check for memory allocation stress conditionsReview system memory limits or resource constraints that could cause realloc() to fail during PNG processingAffected if The system operates under memory-constrained conditions where realloc() failures are plausible
A system is affected if SWFTools version 0.9.2 is installed and is used to process PNG files, particularly when the lib/png.c source contains the unvalidated realloc() pattern in the png_load function.
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 to a patched version of SWFTools if available; otherwise, avoid processing untrusted PNG files with vulnerable SWFTools installations.
- Consultation2.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-16796 — 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-2017-16796 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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