CVE-2026-66398
CRITICALDescription
phpMyFAQ before v4.1.6 contains a remote code execution vulnerability in the configuration API that allows authenticated administrators with CONFIGURATION_EDIT and ATTACHMENT_ADD privileges to write arbitrary PHP files by manipulating the upgrade.lastDownloadedPackage setting. Attackers can upload a malicious ZIP file as an attachment, point the updater configuration to its stored path, and extract it into the application root to achieve code execution as the web server user.
How to fix
No published remediation has been found for this vulnerability's affected products yet.
Mitigation guidance may be in the linked vendor advisories in the References section below.
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CVSS v4 Vector
Exploitability
Impact
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Exploit Intelligence
Low risk: more likely to be exploited than 25% of all known CVEs.
References
Related Vulnerabilities
Other CWE-494 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2020-5398 | High | 7.5 | 88% | - | Fix |
| CVE-2022-40799 | High | 8.8 | 32% | KEV | - |
| CVE-2026-3502 | High | 7.8 | 5.7% | KEV | Fix |
| CVE-2018-19234 | High | 8.8 | 3.3% | - | Fix |
| CVE-2016-6567 | Critical | 9.8 | 2.9% | - | - |
| CVE-2016-6564 | High | 8.1 | 2.7% | - | - |
Common questions
How do I fix CVE-2026-66398?
No published fix for CVE-2026-66398 has been found yet. Check the linked vendor advisories for guidance as it becomes available.
Is CVE-2026-66398 being actively exploited?
Not that we know of. CVE-2026-66398 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.33% is the estimated probability that it will be exploited in the next 30 days. That is higher than 25% of all scored CVEs.
How severe is CVE-2026-66398?
CVE-2026-66398 has a CVSS v4 base score of 9.4, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
Embed a live status badge for CVE-2026-66398
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-07-28.