Security readout for executives and security teams
Plain-English summary
A malicious PDF or webpage could make Foxit PDF Reader run attacker-controlled code when a user opens it. The issue is in JPG2000/PDF parsing and affects Foxit PDF Reader 11.0.1.49938. This is high risk for endpoints where users receive or browse untrusted documents.
Executive priority
Treat as a high-priority endpoint remediation item, especially for staff handling external PDFs. It is not marked KEV in the bundle, but successful exploitation could compromise the user’s workstation with confidentiality, integrity, and availability impact.
Technical view
CVE-2021-34971 is a heap-based buffer overflow (CWE-122) caused by insufficient validation of user-supplied length data before copying into heap memory during PDF parsing. ZDI states attackers can execute code in the current process. CVSS is 7.8 with local attack vector and required user interaction.
Likely exposure
Exposure is most likely on workstations running Foxit PDF Reader 11.0.1.49938 that open PDFs from email, web downloads, portals, or shared drives. Servers are less likely exposed unless they process PDFs with Foxit Reader interactively.
Exploitation context
The sources describe remote code execution requiring user interaction: visiting a malicious page or opening a malicious file. The bundle does not identify CISA KEV listing or active exploitation evidence, so active exploitation should not be assumed.
Researcher notes
The strongest public technical detail is ZDI’s description: malformed PDF parsing, length validation failure, heap buffer overflow, and code execution in the current process. The bundle names Foxit PDF Reader 11.0.1.49938 only; do not infer additional affected versions without vendor confirmation.
Mitigation direction
- Inventory Foxit PDF Reader installations and identify version 11.0.1.49938.
- Check Foxit security bulletins for the vendor-approved fixed version or mitigation.
- Upgrade affected installations according to Foxit guidance.
- Limit automatic opening of PDFs from email, browsers, and untrusted sources.
Validation and detection
- Confirm endpoint software inventory includes Foxit PDF Reader version details.
- Validate whether version 11.0.1.49938 remains installed anywhere.
- Review email and web controls for untrusted PDF handling.
- Confirm vendor bulletin review and remediation records are documented.
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-122: 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-2021-34971 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
- ZDI-21-1202CVE reference · x_research-advisory
- vendor-provided URLCVE reference · vendor-advisory
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.
Heap-based Buffer Overflow
Heap-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.