How to Fix CVE-2026-3778: Foxit PDF Editor (Bundle Sibling)
*By Sai Kiran Pandrala*
Last verified: 2026-05-25
| Severity | CVSS 6.2, Medium |
|---|---|
| Actively exploited? | No |
| Affected | Foxit Software Inc. Foxit PDF Editor (Versions 2025.3 and earlier, Versions 14.0.2 and earlier); Foxit Software Inc. Foxit PDF Reader (Versions 2025.3 and earlier) |
| Fixed in | Same patched build as CVE-2026-3774 |
| Type (CWE) | CWE-674: CWE-674: Uncontrolled Recursion |
CVE-2026-3778 is a sibling vulnerability in the same Foxit Software Inc. Foxit PDF Editor advisory bundle as CVE-2026-3774. The same patched build closes every CVE in the bundle, so the remediation procedure for CVE-2026-3778 matches the primary write-up.
What is different about CVE-2026-3778?
The application does not detect or guard against cyclic PDF object references while handling JavaScript in PDF. When pages and annotations are crafted that reference each other in a loop, passing the document to APIs (e.g., SOAP) that perform deep traversal can cause uncontrolled recursion, stack exhaustion, and application crashes.
Impact is consistent with the bundle: compromise of the affected component as described in the vendor advisory. The patched build closes every code path in the advisory in one update.
How to fix CVE-2026-3778
Apply the patched build per the primary write-up: How to Fix CVE-2026-3774.
For a quick check, confirm the running version of Foxit PDF Editor:
# Confirm the installed version via your package manager
dpkg -l | grep -i foxit # Debian/Ubuntu
rpm -qa | grep -i foxit # RHEL/CentOS/Rocky
Frequently asked questions
Is CVE-2026-3778 being actively exploited?
Not at the time of writing. It is not listed in CISA's Known Exploited Vulnerabilities catalog. That status can change, so monitor the vendor advisory and the KEV catalog if the system is exposed.
How severe is CVE-2026-3778?
CVSS rates it 6.2 (Medium). Use that score to set your patch priority alongside the other items in your queue.
Do I have to take Foxit PDF Editor offline to apply the patch?
It depends on the deployment. High-availability or clustered installs can usually patch one node at a time with no full outage. Standalone installs typically need a short restart. Always follow the vendor's documented upgrade steps.
What if my vulnerability scanner still flags CVE-2026-3778 after I patch?
Re-run the scan after a service restart, then confirm the scanner's plugin set is up to date. Some scanners detect by banner version only and lag the official fix metadata by a release.
References
- Official vendor advisory: https://www.foxit.com/support/security-bulletins.html
- NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2026-3778
- CISA KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
- Primary write-up: How to Fix CVE-2026-3774
*Written by Sai Kiran Pandrala. Last verified 2026-05-25. Part of the Foxit Software Inc. Foxit PDF Editor advisory bundle. Full procedure at how-to-fix-cve-2026-3774.*