Security readout for executives and security teams
Plain-English summary
CVE-2021-31443 is a Foxit Reader flaw where a crafted PDF or web page can make the application read memory it should not. Exploitation requires the user to open a malicious file or visit a malicious page. The disclosed impact is limited information exposure, with possible use in a larger exploit chain.
Executive priority
Treat this as routine patch management, not an emergency. It requires user interaction and has low standalone severity, but PDF readers are common phishing targets, so affected business endpoints should be updated through the normal security maintenance cycle.
Technical view
Foxit Reader 10.1.1.37576 mishandles U3D objects embedded in PDF files. Missing validation of user-supplied data can cause an out-of-bounds read, mapped to CWE-125. The CVSS 3.0 score is 3.3 with user interaction required and confidentiality impact only.
Likely exposure
Exposure is limited to systems running Foxit Reader 10.1.1.37576, especially endpoints where users receive external PDFs or browse untrusted content. The source bundle does not identify other affected Foxit products or versions.
Exploitation context
The source states remote attackers can trigger the flaw only with user interaction: opening a malicious file or visiting a malicious page. CISA KEV status is false, and the provided sources do not claim active exploitation.
Researcher notes
ZDI tracked this as ZDI-21-532 and ZDI-CAN-13240. The flaw is an out-of-bounds read in U3D PDF object handling. Sources note it may aid arbitrary code execution only when combined with other vulnerabilities; they do not provide standalone code-execution impact.
Mitigation direction
- Identify endpoints running Foxit Reader 10.1.1.37576.
- Follow Foxit's security bulletin and update guidance for affected installations.
- Prioritize users who handle external or unsolicited PDF files.
- Reinforce controls against opening untrusted PDFs or links.
- Use current endpoint protection and document-handling policy controls.
Validation and detection
- Check software inventory for Foxit Reader 10.1.1.37576.
- Confirm installed Foxit versions against Foxit security bulletin guidance.
- Review vulnerability scan results for CVE-2021-31443 coverage.
- Verify high-risk users are not using the affected version.
- Document exceptions where updates cannot be applied promptly.
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-125: 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-2021-31443 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
- Low
- CVSS
- 3.3 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
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:L/I:N/A:N1.81.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
3.3LowVector: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
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-21-532/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 Read
Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.