Security readout for executives and security teams
Plain-English summary
A malicious PDF or web page could make Foxit PDF Reader run attacker-controlled code when opened by a user. The known affected version is Foxit PDF Reader 11.0.0.49893. This is serious for organizations where PDFs arrive by email, web download, or ticketing workflows.
Executive priority
Treat as a high-priority workstation remediation item, not an internet-facing server emergency. The business risk is user-driven compromise through malicious PDFs, with potential confidentiality, integrity, and availability impact on affected endpoints.
Technical view
CVE-2021-34840 is a code execution flaw in Foxit PDF Reader's Annotation object handling. The issue is tied to missing validation that an object exists before operations are performed, mapped to CWE-416. Exploitation requires user interaction and runs code in the current process context.
Likely exposure
Exposure is mainly user workstations running Foxit PDF Reader 11.0.0.49893, especially users who open external PDFs or browse untrusted pages.
Exploitation context
The bundle does not show CISA KEV listing or other evidence of active exploitation. The attacker still needs the user to open a malicious file or visit a malicious page.
Researcher notes
The source bundle identifies Foxit PDF Reader 11.0.0.49893, CVSS 7.8, CWE-416, and ZDI-CAN-14021. It does not provide exploit-in-the-wild evidence, detailed affected build ranges, or a specific fixed version in the included text.
Mitigation direction
- Inventory Foxit PDF Reader versions and identify 11.0.0.49893 installations.
- Apply Foxit guidance from the referenced security bulletin.
- Prioritize users who frequently handle external PDFs.
- Use endpoint controls to limit untrusted PDF execution paths.
- Educate users to avoid unexpected PDF attachments and links.
Validation and detection
- Confirm installed Foxit PDF Reader versions on endpoints.
- Check whether any 11.0.0.49893 systems remain in production.
- Review Foxit security bulletin guidance for the applicable fixed release.
- Verify update deployment through endpoint management reporting.
- Monitor mail and web controls for suspicious PDF delivery attempts.
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-2021-34840 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-21-922/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.