Security readout for executives and security teams
Plain-English summary
Foxit Reader 11.0.0.49893 has a high-severity memory safety flaw. A malicious PDF, or a malicious site when the browser plugin is enabled, can lead to arbitrary code execution after user interaction.
Executive priority
Treat this as a high-priority endpoint remediation issue where Foxit Reader is deployed, because compromise requires only user interaction and can affect confidentiality, integrity, and availability.
Technical view
CVE-2021-21893 is a CWE-416 use-after-free in Foxit Reader’s JavaScript engine. The CVSS 3.0 score is 8.8, with network attack vector, low complexity, no privileges required, user interaction required, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most likely on workstations running Foxit Reader 11.0.0.49893, especially users who receive external PDFs or browse with the Foxit browser plugin enabled.
Exploitation context
The sources describe malicious document and browser-plugin attack paths, but the provided bundle does not show CISA KEV listing or active exploitation evidence.
Researcher notes
The available evidence identifies one affected version and vulnerability class, but does not provide exploit status or remediation details in the bundle. Avoid broadening scope beyond Foxit Reader 11.0.0.49893 without vendor confirmation.
Mitigation direction
- Inventory Foxit Reader installations and prioritize version 11.0.0.49893.
- Check Foxit and Talos guidance for fixed versions or official mitigations.
- Disable the Foxit browser plugin extension where present.
- Restrict opening PDFs from untrusted email, downloads, or websites until remediated.
Validation and detection
- Confirm installed Foxit Reader versions across managed endpoints.
- Check whether the Foxit browser plugin extension is enabled.
- Review email and web controls for handling untrusted PDF attachments.
- Verify remediation status against vendor guidance, not assumptions.
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-2021-21893 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
- 8.8 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/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:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
8.8HighVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://talosintelligence.com/vulnerability_reports/TALOS-2021-1336CVE 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.