Security readout for executives and security teams
Plain-English summary
CVE-2021-34834 is a high-severity code execution flaw in Foxit PDF Reader 11.0.0.49893. An attacker needs a user to open a malicious PDF or visit a malicious page. Successful exploitation could run code with the user’s privileges, affecting confidentiality, integrity, and availability.
Executive priority
Treat as priority remediation for affected desktops, especially high-risk user groups. The risk is meaningful but not currently evidenced as actively exploited in the provided sources.
Technical view
The flaw is in Foxit PDF Reader’s handling of Annotation objects. The source says the application fails to validate an object exists before operating on it, mapped to CWE-416. ZDI states remote attackers can execute arbitrary code in the current process after user interaction.
Likely exposure
Exposure is likely limited to systems running Foxit PDF Reader 11.0.0.49893, especially where users receive external PDFs or browse untrusted content.
Exploitation context
The provided sources do not show CISA KEV listing or active exploitation. Exploitation requires user interaction through a malicious page or file.
Researcher notes
ZDI identifies this as ZDI-CAN-14014 and describes user-assisted remote code execution in the current process. Evidence is specific to Foxit PDF Reader 11.0.0.49893; do not broaden affected versions without vendor confirmation.
Mitigation direction
- Identify and prioritize Foxit PDF Reader 11.0.0.49893 installations.
- Check Foxit security bulletins for the vendor-confirmed fixed build.
- Upgrade or remove affected installations according to vendor guidance.
- Limit opening unsolicited PDFs and untrusted links until remediated.
- Use endpoint controls to reduce impact from unexpected PDF Reader behavior.
Validation and detection
- Inventory endpoints for Foxit PDF Reader 11.0.0.49893.
- Compare installed versions against Foxit’s security bulletin.
- Review exposure among users handling external PDF attachments.
- Check EDR for suspicious Foxit PDF Reader child processes or crashes.
- Confirm remediation through software inventory after updates or removal.
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-2021-34834 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-21-916/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.