CVE-2020-21830
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 vulneraibility exists in GNU LibreDWG 0.10 via bit_calc_CRC ../../src/bits.c:2213.
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 · moderate confidenceA heap-based buffer overflow vulnerability exists in GNU LibreDWG version 0.10 in the bit_calc_CRC function located in src/bits.c at line 2213. This memory corruption issue could allow an attacker to execute arbitrary code or cause a denial of service 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.
-
Check if GNU LibreDWG is installedRun 'which dwg2dxf' or 'dwg2dxf --version' to locate the binaries, or search for libredwg shared library files (libredwg.so or libredwg.a) in /usr/lib/ or /usr/local/lib/Affected if LibreDWG binaries or library files are present on the system
-
Determine the installed versionRun 'dwg2dxf --version' or use your package manager to query the installed package version (dpkg -l libredwg or rpm -qa | grep redwg)Affected if The installed version is exactly 0.10
-
Confirm the vulnerable code existsLocate the src/bits.c file in the installed package or source directory and verify that the bit_calc_CRC function is present around line 2213, or use 'strings' on the libredwg library binary to search for 'bit_calc_CRC'Affected if The bit_calc_CRC function exists in the installed version
-
Identify DWG file processingReview any applications or scripts that invoke LibreDWG tools (dwg2dxf, dwgread, etc.) to process DWG files, particularly from untrusted sourcesAffected if Applications process DWG files using the vulnerable LibreDWG library
You are affected if GNU LibreDWG version 0.10 is installed and is used to process DWG files, as the heap overflow in bit_calc_CRC triggers during DWG file parsing.
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 · scopedUpgrade to a patched version of GNU LibreDWG that addresses the buffer overflow in bit_calc_CRC. If upgrading is not immediately possible, sanitize or reject untrusted DWG input files until the patch can be applied.
Upgrade to Libredwg version 0.12 or later stable release
- 1. Check current installed version of Libredwg using: pkg-config --modversion libredwg or dwg2dxf --version
- 2. Identify the latest stable release from https://github.com/LibreDWG/libredwg/releases
- 3. Download the source code for the latest stable release (version 0.12 or later)
- 4. Extract the archive and navigate to the source directory
- 5. Run ./configure to prepare the build
- 6. Run make to compile the software
- 7. Run make install to install the updated version
- 8. Verify the installation by checking the version again
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 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 $6,176.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-21830 — 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-2020-21830 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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
- No spam, self-promotion, credentials, or personal data