CVE-2026-66398

CRITICALPre-NVD 9.49.4
EchelonGraph scoreLOW confidence

This critical-severity CVE scores 9.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: secondary
Elevated
9.4EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 9.4Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
9.4
EG Score
9.4(low)
EG Risk
58(Track*)
EG Risk 58/100SSVC: Track*

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity94% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
—
EPSS %ILE
—
KEV
Not listed

Published

July 27, 2026

Last Modified

July 27, 2026

Advisory Details (2)

Auto-updated Jul 27, 2026
🔬 Proof of concept available. Patch available. Sources: github.
generic

phpMyFAQ before 4.1.6 Remote Code Execution via Configuration API | Advisories | VulnCheck

https://www.vulncheck.com/advisories/phpmyfaq-before-remote-code-execution-via-configuration-api
github Patch Available🟡 PoC Available

Untrusted update-package path in configuration API allows arbitrary PHP file write · Advisory · thorsten/phpMyFAQ · GitHub

https://github.com/thorsten/phpMyFAQ/security/advisories/GHSA-4fv7-8rr6-rf2w

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 4× in last 7d / 4× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-27 17:19 UTCEG score recompute
  2. 2026-07-27 16:24 UTCEG score recompute
  3. 2026-07-27 16:16 UTCEG score recompute
  4. 2026-07-27 16:16 UTCMITRE cvelistV5first tracked

Frequently asked(4)

What is CVE-2026-66398?
CVE-2026-66398 is a critical vulnerability published on July 27, 2026. phpMyFAQ before v4.1.6 contains a remote code execution vulnerability in the configuration API that allows authenticated administrators with CONFIGURATIONEDIT and ATTACHMENTADD privileges to write arbitrary PHP files by manipulating the upgrade.lastDownloadedPackage setting. Attackers can upload a…
When was CVE-2026-66398 disclosed?
CVE-2026-66398 was first published in the National Vulnerability Database on July 27, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-66398?
CVE-2026-66398 has a CVSS v3 base score of 9.4 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-66398?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66398, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-66398

Explore →

Is Your Infrastructure Affected by CVE-2026-66398?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs