Security readout for executives and security teams
Plain-English summary
A vulnerable Foxit PDF Reader version can be made to run attacker-controlled code if a user opens a malicious PDF or visits a malicious page. This is a workstation risk: compromise depends on user interaction, but successful exploitation could give the attacker the same access as the user.
Executive priority
Treat this as a high-priority endpoint remediation item, especially where staff routinely handle external PDFs. It is not confirmed as actively exploited in the provided sources, but successful compromise could affect confidentiality, integrity, and availability.
Technical view
Foxit PDF Reader 11.0.0.49893 mishandles Annotation objects. The flaw is described as missing validation that an object exists before use, mapped to CWE-416, allowing arbitrary code execution in the current process after user interaction.
Likely exposure
Exposure is limited to installations of Foxit PDF Reader 11.0.0.49893 identified in the source bundle. Organizations with unmanaged desktop software, email-delivered PDFs, or browser-based PDF workflows should prioritize inventory.
Exploitation context
The source bundle does not show CISA KEV listing or confirmed active exploitation. Exploitation requires a user to open a malicious file or visit a malicious page, so phishing or document-lure delivery is the likely context.
Researcher notes
ZDI tracks this as ZDI-CAN-14529 / ZDI-21-932. The key technical point is object-lifetime validation around Annotation object handling. The bundle does not provide exploit details, fixed versions, or named mitigations beyond vendor references.
Mitigation direction
- Identify endpoints running Foxit PDF Reader 11.0.0.49893.
- Review Foxit security bulletins for vendor-provided update guidance.
- Update or remove affected Foxit Reader installations per vendor guidance.
- Prioritize high-risk users handling external PDF attachments.
- Use email and web controls to reduce malicious PDF delivery.
Validation and detection
- Query software inventory for Foxit PDF Reader 11.0.0.49893.
- Confirm remediation status against Foxit’s security bulletin.
- Review EDR alerts for suspicious Foxit Reader child processes.
- Check mail and web telemetry for suspicious PDF lures.
- Document any exceptions with owner and remediation date.
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-2021-34850 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.foxit.com/support/security-bulletins.htmlCVE reference · x_refsource_MISC
- https://www.zerodayinitiative.com/advisories/ZDI-21-932/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.