CVE-2020-21833
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 heap based buffer overflow vulnerability exits in GNU LibreDWG 0.10 via: read_2004_section_classes ../../src/decode.c:2440.
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 heap-based buffer overflow vulnerability exists in GNU LibreDWG version 0.10 in the read_2004_section_classes function in src/decode.c at line 2440. This occurs during DWG file parsing when processing section class data without proper bounds checking, allowing an attacker to potentially execute arbitrary code via a specially crafted malicious DWG 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= 0.10CVSS 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
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/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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Check installed GNU LibreDWG versionRun 'redwg --version' or 'libredwg-config --version' to determine the installed version of GNU LibreDWGAffected if The version is exactly 0.10
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Verify DWG file processing is occurringCheck if your application or tool processes DWG files using LibreDWG library functions, particularly decode/parsing operationsAffected if DWG files are being parsed or decoded using the vulnerable version
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Identify use of read_2004_section_classes functionReview application logs or code that invokes LibreDWG decoding routines to see if section class data from DWG files is being processedAffected if The application parses DWG files containing section class data in version 0.10
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Confirm library linkage to vulnerable versionCheck the shared library file (typically libredwg.so or libredwg.a) and its version metadata using 'ldd' on the executable or 'dpkg -l | grep libredwg' / 'rpm -qa | grep libredwg'Affected if The linked library resolves to version 0.10
You are affected if GNU LibreDWG version 0.10 is installed AND your environment processes DWG files using the parsing functionality where section class data is handled.
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 dataUpgrade to GNU LibreDWG version 0.10.1 or later which contains the fix for this heap overflow vulnerability. If upgrading is not immediately feasible, implement file parsing validation and consider restricting processing of untrusted DWG files.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2020-21833 — 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-2020-21833 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
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