CVE-2020-21841
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 bit_read_B ../../src/bits.c:135.
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 confidenceHeap-based buffer overflow vulnerability in the bit_read_B function in GNU LibreDWG 0.10 (src/bits.c:135). The function fails to properly validate buffer boundaries when reading bit data, allowing an attacker to overflow the heap allocation via specially crafted DWG files.
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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Identify installed Libredwg versionRun 'redwg --version' or check the library version via package manager (dpkg -l | grep redwg, rpm -qa | grep redwg, or pkg-config --modversion redwg)Affected if Version returned is exactly 0.10
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Locate the vulnerable library fileFind the shared library: typically /usr/lib/libredwg.so.0 or similar path. Use 'find /usr -name "libredwg*" 2>/dev/null' or check compile-time installationAffected if Libredwg version 0.10 shared library exists on the system
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Check for DWG file processing applicationsInspect running processes or audit logs for applications that invoke Libredwg to parse DWG files (search for 'redwg' command execution or applications linking to libredwg)Affected if Any application uses Libredwg to read or process DWG files
A system is affected if GNU LibreDWG version 0.10 is installed and actively used to process DWG files, as the heap overflow in bit_read_B triggers when parsing specially crafted DWG data.
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.
dbcve · scopedUpdate to a patched version of GNU LibreDWG. Until patched, limit processing of untrusted DWG files and consider applying input validation or sandboxing as a defense-in-depth measure.
Upgrade to LibreDWG 0.12 or later (latest stable release)
- 1. Identify the current installed version of LibreDWG by running: `libredwg-config --version` or checking your package manager
- 2. Download the latest stable release from the official GitHub repository: https://github.com/LibreDWG/libredwg/releases
- 3. For source-based installation: clone the repository and build from the latest release tag
- 4. For package managers: update to the latest available package version from your distribution's repository
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation6.0 h
- Testing12.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,040.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-21841 — 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-2020-21841 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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