dbcve.org
FedoraOperating system · Fedoraproject

CVE-2020-35628

CRITICAL · 9.8 CVSS v3.1 Published 2021-03-04
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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 · unedited
A code execution vulnerability exists in the Nef polygon-parsing functionality of CGAL libcgal CGAL-5.1.1. An oob read vulnerability exists in Nef_S2/SNC_io_parser.h SNC_io_parser::read_sloop() slh->incident_sface. An attacker can provide malicious input to trigger this vulnerability.

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 confidence

A critical code execution vulnerability exists in CGAL's Nef polygon-parsing functionality, coupled with an out-of-bounds read vulnerability in the SNC_io_parser::read_sloop() function (slh->incident_sface). Attackers can achieve remote code execution by providing specially crafted malicious polygon data that triggers memory corruption during parsing.

MitigationUpdate CGAL to a patched version (5.1.2 or later). If patching is not immediately feasible, implement strict input validation and sandboxing around any code that processes untrusted polygon/geometry data using CGAL's Nef functionality.

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
FedoraOperating system
Affected:= 33= 34
Debian LinuxOperating system
Affected:= 9.0= 10.0
Computational Geometry Algorithms LibraryApplication
Affected:= 5.1.1

CVSS 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
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify CGAL installation and version
    Check if CGAL library is installed. On Debian/Ubuntu: dpkg -l | grep libcgal-dev or rpm -qa | grep CGAL. On systems with pkg-config: pkg-config --modversion CGAL. Check build files (CMakeLists.txt) for CGAL version requirements.
    Affected if CGAL version is 5.1.1 exactly, or falls within the affected version range before 5.1.2
  2. Verify if code uses Nef polygon functionality
    Search source code for Nef-related headers: #include <CGAL/Nef_...>, usage of CGAL::Nef_polyhedron, CGAL::Nef_complex, or similar Nef* classes in C++ code or headers.
    Affected if Code imports or uses CGAL's Nef polygon-parsing functionality, particularly for processing polygon data
  3. Check for untrusted polygon/geometry input handling
    Audit code paths that parse polygon data (from files, network, user input) that flow into CGAL::read_polygon_mesh(), CGAL::Nef_polyhedron_2::read(), or similar parsing functions. Look for file read operations or data deserialization passing data to CGAL.
    Affected if Application processes untrusted or externally-sourced polygon/geometry data through CGAL's Nef parser
  4. Identify runtime environment and exposure
    Check if application runs in an exposed manner (network service, file upload handler, or processes data from untrusted sources). Review if CGAL is used in server-side code, desktop applications, or tools that handle third-party geometry files.
    Affected if CGAL's Nef parser processes data from untrusted or network-accessible sources without sanitization

A system is affected if CGAL version 5.1.1 is installed AND code uses the Nef polygon-parsing functionality to process any polygon/geometry data, especially from untrusted sources.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update CGAL to a patched version (5.1.2 or later). If patching is not immediately feasible, implement strict input validation and sandboxing around any code that processes untrusted polygon/geometry data using CGAL's Nef functionality.

Recommended fix Moderate confidence

CGAL 5.1.2 or later (or latest stable release)

  1. Check your system's installed CGAL version using your package manager (e.g., 'rpm -q cgal' on Fedora or 'dpkg -l libcgal-dev' on Debian)
  2. For Fedora systems: Run 'sudo dnf update' to fetch and apply the latest security patches including the CGAL fix
  3. For Debian systems: Run 'sudo apt-get update && sudo apt-get upgrade' to apply available security updates
  4. Verify the update was successful by checking the new CGAL version
  5. If building from source, obtain CGAL-5.1.2 or later from https://www.cgal.org/download.html
Caveat Minor release upgrade within 5.x series - unlikely to introduce breaking changes in API, but verify any custom code using Nef polygon-parsing functionality

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Fedora Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,760
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-35628 in production — separate from our analysis above.

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What this is

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What belongs here
  • 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
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