Security readout for executives and security teams
Plain-English summary
This flaw lets a malicious PDF or web-delivered document trigger code execution in Foxit PDF Editor, but the victim must open the file or visit a malicious page. The impact is serious for users who handle external PDFs because successful exploitation runs code as that user.
Executive priority
Treat this as a high-priority endpoint remediation item for teams that process external PDFs. Prioritize inventory and vendor-guided updates before broader hardening work. Urgency is lower than confirmed exploited vulnerabilities, but business impact is high if a targeted user opens a weaponized document.
Technical view
CVE-2021-34958 is a CWE-416 use-after-free in Foxit PDF Editor text annotation handling. The flaw involves operations on an Annotation object without validating that it still exists. Sources identify Foxit PDF Editor 11.0.0.49893 as affected, with CVSS 3.0 score 7.8.
Likely exposure
Exposure is most likely on endpoints running Foxit PDF Editor 11.0.0.49893, especially users who open PDFs from email, downloads, portals, or web pages. The source bundle does not establish other affected versions.
Exploitation context
The sources describe remote code execution requiring user interaction. The target must open a malicious file or visit a malicious page. The CVE is not marked KEV in the bundle, and no cited source here confirms active exploitation.
Researcher notes
Evidence is specific about the bug class, affected product/version, user interaction, and impact. The bundle does not provide exploit status, fixed version details, or broad version ranges. Avoid expanding the affected set without Foxit confirmation.
Mitigation direction
- Inventory Foxit PDF Editor installations and versions across managed endpoints.
- Check Foxit security bulletins for fixed versions or vendor-required remediation.
- Update or remove Foxit PDF Editor 11.0.0.49893 where present.
- Filter or sandbox externally sourced PDFs for higher-risk users.
- Reinforce user handling rules for unexpected PDFs and links.
Validation and detection
- Confirm whether any endpoint runs Foxit PDF Editor 11.0.0.49893.
- Compare deployed Foxit versions against Foxit security bulletin guidance.
- Review endpoint telemetry for suspicious Foxit PDF Editor child processes or crashes.
- Verify email and web controls inspect or isolate untrusted PDF content.
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-2021-34958 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-21-1189CVE 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.