Security readout for executives and security teams
Plain-English summary
CVE-2021-31455 is a high-severity Foxit Reader flaw where a crafted file or page can lead to code execution after user interaction. Business risk is concentrated on endpoints running Foxit Reader 10.1.1.37576, especially users who handle untrusted PDFs or links.
Executive priority
Treat this as a priority endpoint remediation item, not an internet-edge emergency. The impact is severe if triggered, but exploitation requires user interaction and the provided evidence does not show known active exploitation.
Technical view
The issue affects Foxit Reader 10.1.1.37576 in XFA form handling. The flaw involves operating on an object without validating its existence, mapped to CWE-416. Successful exploitation can execute code in the current process with confidentiality, integrity, and availability impact.
Likely exposure
Exposure is likely limited to organizations with Foxit Reader 10.1.1.37576 installed. Risk is higher where users receive external PDFs, browse untrusted sites, or process documents from unknown sources. The bundle does not identify other affected Foxit products or versions.
Exploitation context
The source bundle says user interaction is required: the target must visit a malicious page or open a malicious file. KEV is false, and the provided sources do not establish active exploitation in the wild.
Researcher notes
Key research focus is XFA form parsing in Foxit Reader 10.1.1.37576 and object lifetime validation. Do not assume broader product impact from this bundle alone. Patch details are not included here, so rely on Foxit guidance for exact fixed builds.
Mitigation direction
- Inventory endpoints for Foxit Reader 10.1.1.37576.
- Check Foxit security bulletins for fixed versions and vendor guidance.
- Prioritize update or removal on externally exposed document-handling workstations.
- Warn users against opening untrusted PDFs or document links.
- Use mail and web filtering to reduce delivery of suspicious PDFs.
Validation and detection
- Confirm installed Foxit Reader versions through endpoint inventory.
- Verify remediation against Foxit security bulletin guidance.
- Review whether affected users routinely handle external PDFs.
- Check security tooling for suspicious Foxit Reader child processes.
- Document any compensating controls if patching is delayed.
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-2021-31455 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-21-544/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.