Security readout for executives and security teams
Plain-English summary
CVE-2021-34837 is a high-severity code execution flaw in Foxit PDF Reader 11.0.0.49893. A user must open a malicious file or visit a malicious page. If successful, an attacker can run code as the current user, creating risk of data theft, malware installation, and workstation compromise.
Executive priority
Treat this as a high-priority endpoint remediation item, not a confirmed active emergency. The business risk is meaningful because successful exploitation gives code execution, but the attacker needs user interaction and the provided sources do not show active exploitation.
Technical view
The flaw affects Annotation object handling in Foxit PDF Reader 11.0.0.49893. The source describes missing validation that an object exists before operations are performed on it, mapped to CWE-416. Successful exploitation can execute code in the current process. ZDI tracked it as ZDI-CAN-14018 and ZDI-21-919.
Likely exposure
Exposure is likely limited to endpoints running Foxit PDF Reader 11.0.0.49893, especially users who open external PDFs or browse untrusted web content. The provided sources do not identify other Foxit products or versions as affected.
Exploitation context
The source states remote attackers can trigger code execution, but user interaction is required. The target must open a malicious file or visit a malicious page. The CVE is not listed as KEV in the provided bundle, and no cited source confirms active exploitation.
Researcher notes
Focus analysis on Foxit PDF Reader 11.0.0.49893 and Annotation object parsing. Evidence supports high impact, local user context execution, and required interaction. Do not broaden affected scope beyond the cited CVE/ZDI/Foxit references without additional vendor evidence.
Mitigation direction
- Inventory endpoints for Foxit PDF Reader 11.0.0.49893.
- Check Foxit security bulletins for the supported update or remediation path.
- Prioritize upgrading or removing the affected version where found.
- Limit opening PDFs from untrusted sources until remediation is complete.
- Use email and web controls to reduce delivery of suspicious PDF content.
Validation and detection
- Confirm installed Foxit PDF Reader versions through endpoint inventory.
- Verify affected systems no longer run version 11.0.0.49893.
- Check Foxit advisory status before marking remediation complete.
- Review EDR and email telemetry for suspicious PDF-related activity.
- Validate controls without attempting exploit reproduction in production.
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-2021-34837 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-21-919/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.