Security readout for executives and security teams
Plain-English summary
CVE-2021-34845 is a high-severity Foxit PDF Reader flaw that can let an attacker run code if a user opens a malicious PDF or visits a malicious page. The known affected version in the bundle is Foxit PDF Reader 11.0.0.49893. It is serious, but the sources do not show confirmed active exploitation.
Executive priority
Treat this as a high-priority endpoint patching issue where Foxit PDF Reader is deployed. It can lead to code execution, but needs user interaction and lacks source-backed evidence of active exploitation in the provided bundle.
Technical view
The flaw is in Foxit PDF Reader handling of Annotation objects. It involves failing to validate an object exists before operating on it, mapped to CWE-416. Successful exploitation requires user interaction and can execute code in the current process context. CVSS 3.0 is 7.8: AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
Likely exposure
Organizations are exposed where Foxit PDF Reader 11.0.0.49893 is installed and users can open PDFs or web-delivered content from untrusted sources. Exposure is endpoint-focused, not a server-side internet-facing condition based on the supplied sources.
Exploitation context
The bundle describes remote attacker delivery through a malicious page or file, but user interaction is required. CISA KEV status is false in the provided data, and no cited source in the bundle confirms in-the-wild exploitation.
Researcher notes
Key validation points are product/version match, Foxit Reader 11.0.0.49893 presence, and user exposure to untrusted PDFs or pages. The advisory identifies Annotation object handling and object-existence validation as the vulnerable area. The bundle does not provide exploit details or a specific fixed version.
Mitigation direction
- Inventory endpoints for Foxit PDF Reader 11.0.0.49893.
- Review Foxit’s security bulletin for the vendor-approved update path.
- Upgrade or remove vulnerable Foxit PDF Reader installations according to vendor guidance.
- Limit opening PDFs from untrusted email, web, and external sources until remediated.
Validation and detection
- Confirm the installed Foxit PDF Reader version on managed endpoints.
- Compare installed versions against Foxit’s security bulletin guidance.
- Verify vulnerable version 11.0.0.49893 is no longer present after remediation.
- Check email and web controls for handling of untrusted PDF attachments and links.
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-2021-34845 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-21-927/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.