CVE-2020-21843
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_RC ../../src/bits.c:318.
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_read_RC function in src/bits.c at line 318. The vulnerability allows an attacker to overflow a heap-allocated buffer, potentially leading to arbitrary code execution or denial of service. This is a memory corruption vulnerability in the DWG file parsing library.
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 installed GNU LibreDWG versionRun 'pkg-config --modversion libredwg' or check your package manager for the installed libredwg version (e.g., 'dpkg -l libredwg' or 'rpm -qi libredwg')Affected if Version is exactly 0.10
-
Locate the libredwg library fileFind the shared library on your system using 'find /usr -name "libredwg*" 2>/dev/null' or 'ldconfig -p | grep redwg'Affected if The library file exists and was built from version 0.10
-
Verify the vulnerable source file is presentIf you have the source installed, check for src/bits.c around line 318 containing the bit_read_RC functionAffected if The vulnerable code path exists in your installation
-
Identify applications using libredwgRun 'ldd $(which <your-dwg-tool>) 2>/dev/null | grep redwg' or check processes that load libredwg.soAffected if Applications load libredwg and process DWG files
-
Confirm DWG file processing is occurringMonitor or audit your system for DWG file parsing operations using libredwg-based toolsAffected if DWG files are being processed by the affected library version
You are affected if GNU LibreDWG version 0.10 is installed and is being used to parse DWG files, as the heap overflow in bit_read_RC triggers during DWG input processing.
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 dataUpdate GNU LibreDWG to a version that includes the fix for this vulnerability, or apply a patch to add proper bounds checking in the bit_read_RC function. If updating is not immediately feasible, implement input validation on DWG files before processing to reduce exploitability.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-21843 — 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-2020-21843 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