CVE-2017-6961
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 · uneditedAn issue was discovered in apng2gif 1.7. There is improper sanitization of user input causing huge memory allocations, resulting in a crash. This is related to the read_chunk function using the pChunk->size value (within the PNG file) to determine the amount of memory to allocate.
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 read_chunk function in apng2gif 1.7 uses the chunk size value (pChunk->size) directly from the PNG file to determine memory allocation without proper validation. A malicious PNG file with an excessively large chunk size value can trigger the program to attempt allocating huge amounts of memory, causing a crash via memory exhaustion or allocation failure.
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= 1.7CVSS 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
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:L/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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Identify if apng2gif is installedSearch for the apng2gif binary on the system using file system searches or package managers (e.g., 'which apng2gif', 'dpkg -l | grep apng2gif', 'rpm -qa | grep apng2gif').Affected if The program is found on the system.
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Determine the installed versionRun 'apng2gif --version' or check the binary's metadata/version information. Compare the version number to the affected range (version 1.7).Affected if The version is exactly 1.7.
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Confirm the read_chunk function is in the binaryIf available, inspect the binary for the read_chunk function symbol using tools like 'strings' or a disassembler, or verify the source code version matches 1.7.Affected if The binary corresponds to the 1.7 release containing the vulnerable read_chunk function.
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Verify PNG processing is possibleConfirm the system has PNG files that could be processed by apng2gif, or note that the program accepts PNG input via command line arguments.Affected if The program can be used to process PNG files, which triggers the vulnerable code path.
The environment is affected if apng2gif version 1.7 is installed and can be used to process PNG files, allowing a malicious PNG with an oversized chunk size to trigger excessive memory allocation.
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 dataImplement bounds checking on chunk size values before memory allocation; validate that pChunk->size does not exceed reasonable limits before calling malloc, and handle oversized chunks as invalid input.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-6961 — 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-2017-6961 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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