CVE-2021-3548
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 · uneditedA flaw was found in dmg2img through 20170502. dmg2img did not validate the size of the read buffer during memcpy() inside the main() function. This possibly leads to memory layout information leaking in the data. This might be used in a chain of vulnerability in order to reach code execution.
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 confidenceA buffer size validation vulnerability exists in dmg2img (versions up to 20170502) where memcpy() in the main() function does not validate the read buffer size before copying data. This can leak memory layout information, potentially aiding attackers in bypassing ASLR and constructing exploitation chains to achieve code execution.
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<= 20170502CVSS 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
- None
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/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 if dmg2img is installedRun 'dmg2img --version' or 'which dmg2img' to verify the binary exists on the systemAffected if dmg2img is not installed or the command returns not found - not affected
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Determine the installed dmg2img versionRun 'dmg2img --version' and capture the output. The version string typically includes a date in format YYYYMMDD (e.g., 20170502)Affected if The version number cannot be determined - status unknown, treat as potentially affected
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Compare version against affected rangeParse the version number from step 2 and verify if it is less than or equal to 20170502Affected if Version <= 20170502 confirms the affected version is installed - user is affected
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Verify the vulnerable code path existsInspect the dmg2img binary or source code for the memcpy() call in the main() function that lacks buffer size validation. This requires access to the source or disassemblyAffected if The vulnerable memcpy() without bounds checking is present - confirms exploitability, user is affected
If dmg2img is installed and its version is 20170502 or earlier, the environment is affected by this vulnerability.
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 proper bounds checking to validate buffer sizes before the memcpy() call in the main() function, ensuring the source size does not exceed the destination buffer allocation.
- Consultation2.0 h
- Implementation2.0 h
- Testing4.0 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 $2,464.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-3548 — 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-2021-3548 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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