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CVE-2025-66409

Critical Vulnerability: CVE-2025-66409 — espressif — esp-idf

ESF-IDF is the Espressif Internet of Things (IOT) Development Framework. In 5.5.1, 5.4.3, 5.3.4, 5.2.6, 5.1.6, and earlier, when AVRCP is enabled on ESP32, receiving a malformed VENDOR DEPENDENT command from a peer device can cause the Bluetooth stack to access memory before validating the command buffer length. This may lead to an out-of-bounds read, potentially exposing unintended memory content or causing unexpected behavior.

Sunday, October 18, 2026espressifVulnios Threat Intelligence
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Vulnerability Snapshot

CVE-2025-66409 is rated CRITICAL — exploitation is trivial or already observed in the wild and impact is severe. Patch immediately, not on the next maintenance window.

Affected technology: esp-idf.

Executive Summary

ESF-IDF is the Espressif Internet of Things (IOT) Development Framework. In 5.5.1, 5.4.3, 5.3.4, 5.2.6, 5.1.6, and earlier, when AVRCP is enabled on ESP32, receiving a malformed VENDOR DEPENDENT command from a peer device can cause the Bluetooth stack to access memory before validating the command buffer length. This may lead to an out-of-bounds read, potentially exposing unintended memory content or causing unexpected behavior.

Why It Matters

CVE-2025-66409 is rated CRITICAL severity, requiring immediate attention from security teams.

CVSS Base Score: 9.1/10

EPSS (Exploit Prediction): 0.6% probability of exploitation in the next 30 days.

Affected Technologies

Vendors: espressif

Products: esp-idf

🛡️What Defenders Should Check

  • Check if you are affected — Review your asset inventory for products listed in CVE-2025-66409.
  • Apply available patches — Visit vendor advisories for the latest security updates.
  • Monitor for exploitation — Check your SIEM/IDS logs for related indicators.

    • Use Vulnios to continuously monitor your exposure to CVE-2025-66409 and similar vulnerabilities.

    References & Sources

  • https://github.com/espressif/esp-idf/commit/075ed218cadb8088155521cd8a795d8a626519fb
  • https://github.com/espressif/esp-idf/commit/2f788e59ee361eee230879ae2ec9cf5c893fe372
  • https://github.com/espressif/esp-idf/commit/798029129a71c802cff0e75eb59f902bca8f1946
  • https://github.com/espressif/esp-idf/commit/999710fccf95ae128fe51b5679d6b7c75c50d902
  • https://github.com/espressif/esp-idf/commit/d5db5f60fc1dcfdd8cd3ee898fdefaa272988ace
  • https://github.com/espressif/esp-idf/commit/daeeba230327176b9627b1caa94acdc54065c4b7
  • https://github.com/espressif/esp-idf/security/advisories/GHSA-qhf9-vr2h-jh96

    • How Vulnios Detects This

    Vulnios scans for this vulnerability using Trivy and Grype for SBOM-based CVE matching and Vulnios CVE feed continuous monitoring against your asset inventory. Run a scan against your environment to see whether you are exposed; findings are linked back to the original CVE record so triage starts with the patch path already known.

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    Affected Products

    esp-idf

    Sources

    Related Threat Alerts

    Frequently Asked Questions

    What is CVE-2025-66409?

    CVE-2025-66409 is a critical-severity vulnerability tracked under the Common Vulnerabilities and Exposures program. ESF-IDF is the Espressif Internet of Things (IOT) Development Framework. In 5.5.1, 5.4.3, 5.3.4, 5.2.6, 5.1.6, and earlier, when AVRCP is enabled on ESP32, receiving a malformed VENDOR DEPENDENT comma

    Am I affected?

    Check whether your environment runs esp-idf. If you operate any of those, treat yourself as in scope until you have evidence otherwise. A Vulnios scan will identify the exact assets carrying the affected version.

    How urgent is the response?

    Critical: do not wait for your normal patch cycle. Verify exposure today, apply the vendor patch immediately, and add detection rules for any post-exploit indicators.

    How do I remediate?

    Apply the vendor patch listed in the upstream advisory linked under Sources. If the patch is not yet available, follow the vendor-supplied workaround (often a config flag or feature disable) and add detections for the published exploit pattern in your SIEM. Re-scan after the patch lands to confirm the finding clears.

    Where can I track exploitation activity?

    Watch CISA's Known Exploited Vulnerabilities catalog for CVE-2025-66409. Cross-reference with public exploit databases and your own SIEM/IDS for indicator-of-compromise patterns. Vulnios tracks KEV status automatically and surfaces it on the asset findings view.

    How does Vulnios help with this?

    Vulnios continuously cross-references your asset inventory against the live CVE feed (NVD, vendor advisories, CISA KEV, and curated OSINT). When a new CVE matches your environment, you get a prioritized finding with the severity, KEV status, exploit-prediction (EPSS), and a direct path to the vendor patch. You can start a free scan from the homepage.

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