Security readout for executives and security teams
Plain-English summary
CVE-2021-31451 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 source bundle identifies Foxit Reader 10.1.1.37576. The business risk is workstation compromise through document handling, not unauthenticated network takeover.
Executive priority
Prioritize remediation on user workstations that receive external documents. This is not marked as actively exploited in the supplied evidence, but it can enable code execution after user interaction, making it relevant to phishing-driven compromise.
Technical view
The flaw is in Foxit Reader Annotation object handling. The issue is described as missing validation that an object exists before operations are performed on it, mapped to CWE-416. Successful exploitation can execute code in the current process context and requires user interaction.
Likely exposure
Exposure is likely on endpoints running Foxit Reader 10.1.1.37576, especially users who handle external PDFs or browse untrusted content. The provided sources do not identify additional affected Foxit products or versions.
Exploitation context
The bundle does not show CISA KEV listing or cited active exploitation. Exploitation requires user interaction: opening a malicious file or visiting a malicious page. Treat phishing and external document workflows as the realistic delivery path.
Researcher notes
ZDI-21-540 is referenced as the advisory source and CVE text names ZDI-CAN-13089. Keep analysis scoped to Foxit Reader 10.1.1.37576 unless vendor bulletin review confirms more versions or products.
Mitigation direction
- Inventory endpoints for Foxit Reader 10.1.1.37576.
- Check Foxit’s security bulletin for fixed versions or vendor instructions.
- Upgrade, remove, or isolate affected installations per vendor guidance.
- Limit opening untrusted PDFs until affected clients are remediated.
Validation and detection
- Confirm installed Foxit Reader versions across managed endpoints.
- Verify remediation status against Foxit’s referenced security bulletin.
- Review mail and web controls for external PDF handling risk.
- Confirm no affected legacy installations remain after remediation.
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-416: 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-2021-31451 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-21-540/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.
Use After Free
Use After Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.