Security readout for executives and security teams
Plain-English summary
A malicious PDF or web page could cause Foxit PDF Reader 11.0.0.49893 to run attacker-controlled code when a user opens it. This is high risk for endpoints that handle untrusted documents, but the provided sources do not show active exploitation.
Executive priority
Treat as a high-priority endpoint remediation item, especially for teams exposed to external documents. It is not proven exploited in the provided sources, but successful exploitation could compromise confidentiality, integrity, and availability on affected workstations.
Technical view
The flaw is in Foxit PDF Reader’s handling of Annotation objects. Missing object-existence validation can lead to unsafe operations, mapped to CWE-416, allowing code execution in the current process. Exploitation requires user interaction and no privileges.
Likely exposure
Exposure is limited to installations of Foxit PDF Reader 11.0.0.49893 identified in the source bundle. Risk is highest where users receive external PDFs or browse untrusted sites.
Exploitation context
The attacker must convince a user to open a malicious file or visit a malicious page. The bundle marks KEV as false and provides no cited evidence of active exploitation.
Researcher notes
CVSS 3.0 is 7.8 with AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. ZDI tracks this as ZDI-CAN-14023. The bundle names only Foxit PDF Reader 11.0.0.49893, so broader version impact should not be assumed.
Mitigation direction
- Inventory endpoints for Foxit PDF Reader 11.0.0.49893.
- Check Foxit security bulletins for the vendor-recommended update or workaround.
- Prioritize remediation on systems handling external PDFs.
- Use endpoint controls to limit untrusted document execution paths.
- Educate high-risk users to avoid unexpected PDFs and links.
Validation and detection
- Confirm affected Foxit Reader versions through software inventory.
- Verify remediated systems no longer run version 11.0.0.49893.
- Review Foxit’s bulletin for exact affected and fixed build details.
- Check document-handling endpoints for suspicious PDF delivery patterns.
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-2021-34833 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-21-915/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.