Security readout for executives and security teams
Plain-English summary
This vulnerability can let an attacker run code through Foxit PDF Editor when a user opens a malicious file or visits a malicious page. It affects Foxit PDF Editor 11.0.0.49893 in the provided sources. The business risk is endpoint compromise, not automatic internet-wide server exposure.
Executive priority
Prioritize remediation for users who handle external PDFs, such as finance, legal, sales, support, and executives. This is high severity because it can lead to code execution, but the sources indicate exploitation requires user interaction.
Technical view
CVE-2021-34961 is a CWE-416 use-after-free in Foxit PDF Editor's handling of Annotation objects, specifically Ink Annotation handling. The flaw is missing validation that an object exists before operations are performed on it. Successful exploitation can execute code in the current process context. CVSS is 7.8 high with required user interaction.
Likely exposure
Exposure is most likely on workstations running Foxit PDF Editor 11.0.0.49893, especially where users receive PDFs from email, browsers, portals, or external file exchanges. The source bundle does not identify additional affected versions or products.
Exploitation context
The sources require user interaction: the target must open a malicious file or visit a malicious page. The bundle does not cite CISA KEV listing, active exploitation, public exploit availability, or in-the-wild campaign evidence.
Researcher notes
Evidence supports a use-after-free in Annotation object handling and RCE in the current process. ZDI tracked it as ZDI-CAN-14363 and ZDI-21-1192. The supplied data is incomplete on patch version details, exploit maturity, and telemetry-based exploitation.
Mitigation direction
- Inventory endpoints for Foxit PDF Editor 11.0.0.49893.
- Check Foxit's security bulletins for the vendor-confirmed fixed version.
- Update affected installations according to Foxit's guidance.
- Limit handling of untrusted PDFs on affected endpoints until remediated.
- Use email and web controls to reduce delivery of suspicious PDFs.
Validation and detection
- Confirm installed Foxit PDF Editor versions through asset management.
- Verify whether any endpoint remains on version 11.0.0.49893.
- Review Foxit guidance before marking remediation complete.
- Check endpoint detections involving suspicious PDF files or Foxit process behavior.
- Validate that user-facing PDF workflows still use a supported Foxit version.
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
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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-2021-34961 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
- ZDI-21-1192CVE reference · x_research-advisory
- vendor-provided URLCVE reference · vendor-advisory
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.