Security readout for executives and security teams
Plain-English summary
Foxit Reader 10.1.1.37576 has a document-handling flaw that can let an attacker run code if a user opens a malicious file or visits a malicious page. The issue is serious because successful exploitation can compromise the user’s session, but the provided sources do not show active exploitation.
Executive priority
Treat this as a high-priority workstation remediation item, especially for users exposed to external documents. It is not evidenced here as actively exploited, but successful exploitation could allow full code execution in the user’s application context.
Technical view
CVE-2021-31461 is a CWE-843 type confusion vulnerability in Foxit Reader’s handling of app.media objects. Improper validation of user-supplied data can lead to arbitrary code execution in the current process. CVSS 3.0 score is 7.8 with user interaction required and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is limited to installations of Foxit Reader 10.1.1.37576 identified in the source bundle. Risk is highest on workstations where users receive external PDFs, browse untrusted sites, or handle files from unknown sources.
Exploitation context
The sources describe remote attacker code execution requiring user interaction: the target must open a malicious file or visit a malicious page. CISA KEV status is false in the provided bundle, and no cited source here confirms active exploitation.
Researcher notes
ZDI published this as ZDI-21-550 and references ZDI-CAN-13333. The vulnerable area is app.media object handling, with type confusion caused by insufficient validation. The source bundle does not provide exploit details, proof of exploitation, or a specific fixed version.
Mitigation direction
- Inventory endpoints for Foxit Reader 10.1.1.37576.
- Check Foxit’s security bulletin for the vendor-supported update or mitigation.
- Prioritize updates on systems handling external PDFs.
- Limit opening PDFs from untrusted sources until remediated.
- Use endpoint controls to reduce untrusted document execution risk.
Validation and detection
- Confirm installed Foxit Reader versions across managed endpoints.
- Verify remediation status against Foxit’s security bulletin.
- Check vulnerability scanner findings for CVE-2021-31461.
- Review whether affected users handle external PDFs or web downloads.
- Document exceptions where affected versions remain installed.
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-843: 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-2021-31461 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-21-550/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.
Access of Resource Using Incompatible Type ('Type Confusion')
Access of Resource Using Incompatible Type ('Type Confusion') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.