Security readout for executives and security teams
Plain-English summary
CVE-2021-34852 is a high-severity Foxit PDF Reader flaw that could let an attacker run code when a user opens a malicious PDF or visits a malicious page. It is not a network-only bug; user interaction is required. The source bundle names Foxit PDF Reader 11.0.0.49893 as affected.
Executive priority
Treat as a desktop endpoint patching priority, not an internet-exposed server emergency. The business risk is code execution after user interaction, which matters for phishing and document-driven compromise. Urgency depends on how widely Foxit Reader 11.0.0.49893 is deployed.
Technical view
The flaw is in Foxit PDF Reader handling of Annotation objects. Sources describe missing validation that an object exists before operations are performed, categorized as CWE-416. Successful exploitation can execute code in the current process context. CVSS is 7.8 with local attack vector, low complexity, no privileges, and required user interaction.
Likely exposure
Exposure is most likely on endpoints running Foxit PDF Reader 11.0.0.49893, especially where users receive external PDFs or open browser-delivered documents. The bundle does not identify other affected Foxit products or versions.
Exploitation context
The source bundle says exploitation requires the target to open a malicious file or visit a malicious page. It does not provide evidence of active exploitation, and KEV is false, so active exploitation should not be assumed from these sources.
Researcher notes
Evidence is limited to the CVE record, Foxit bulletin reference, and ZDI advisory reference. Do not broaden affected scope beyond Foxit PDF Reader 11.0.0.49893 without vendor confirmation. No exploit steps, patch version, or active exploitation evidence are included in the provided bundle.
Mitigation direction
- Identify endpoints running Foxit PDF Reader 11.0.0.49893.
- Follow Foxit's security bulletin guidance for the corrected version or workaround.
- Prioritize updates for users who handle external PDFs frequently.
- Limit opening untrusted PDFs or links until affected installs are remediated.
Validation and detection
- Inventory installed Foxit PDF Reader versions across managed endpoints.
- Confirm no systems remain on version 11.0.0.49893.
- Verify vulnerability scanner findings map specifically to CVE-2021-34852.
- Review user groups with high PDF exposure for remediation priority.
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-2021-34852 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-21-934/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.