Security readout for executives and security teams
Plain-English summary
CVE-2021-31473 is a high-severity Foxit Reader flaw that can let an attacker run code if a user opens a malicious file or visits a malicious page. The business risk is endpoint compromise through document handling, especially where staff regularly process external PDFs or web content.
Executive priority
Treat this as a timely endpoint remediation item, not a confirmed emergency. Prioritize teams handling external documents because compromise requires user interaction but can lead to full confidentiality, integrity, and availability impact in the user context.
Technical view
The flaw affects Foxit Reader 10.1.3.37598. ZDI describes an out-of-bounds write in the browseForDoc function caused by insufficient validation of user-supplied data. Successful exploitation can execute code in the current process context. It is mapped to CWE-787 with CVSS 3.0 score 7.8.
Likely exposure
Exposure is likely limited to endpoints running Foxit Reader 10.1.3.37598, especially users who open files from email, web downloads, portals, or external counterparties. The bundle does not identify other Foxit products or versions as affected.
Exploitation context
The sources describe user-assisted exploitation through a malicious page or file. CISA KEV status is false in the bundle, and no cited source here confirms active exploitation in the wild.
Researcher notes
The available bundle supports the affected version, bug class, function name, CVSS score, and user-interaction requirement. It does not provide patch version details, exploit proof, or evidence of active exploitation, so remediation should be tied to Foxit’s bulletin.
Mitigation direction
- Inventory Foxit Reader installations and identify version 10.1.3.37598.
- Check Foxit security bulletins for the vendor-supported update or remediation path.
- Update or remove affected Foxit Reader installations according to vendor guidance.
- Limit opening untrusted PDFs and files from external sources.
- Use endpoint controls to monitor suspicious document-reader child processes.
Validation and detection
- Confirm whether Foxit Reader 10.1.3.37598 exists in endpoint inventory.
- Review vulnerable-user groups that handle untrusted PDFs or web downloads.
- Verify remediated systems no longer report the affected version.
- Check EDR telemetry for unusual Foxit Reader process behavior.
- Document exceptions with owner, business need, and compensating controls.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-787: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-31473 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.8 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
7.8HighVector: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://www.foxitsoftware.com/support/security-bulletins.phpCVE reference · x_refsource_MISC
- https://www.zerodayinitiative.com/advisories/ZDI-21-561/CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Out-of-bounds Write
Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.