CVE-2026-42855
7.5 · HIGHOverview
CVE-2026-42855 is a high-severity vulnerability affecting espressif arduino-esp32. It was published on May 12, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
arduino-esp32 is an Arduino core for the ESP32, ESP32-S2, ESP32-S3, ESP32-C3, ESP32-C6 and ESP32-H2 microcontrollers. Prior to 3.3.8, the WebServer Digest authentication implementation in arduino-esp32 computes the authentication hash using the URI field from the client's Authorization header, without verifying that it matches the actual requested URI. This allows an attacker who possesses any valid digest response (computed for URI-A) to authenticate requests to a completely different protected URI (URI-B), bypassing per-resource access control. This vulnerability is fixed in 3.3.8.
Remediation
Check the references section for vendor advisories and patches from espressif. Update arduino-esp32 to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| espressif | arduino-esp32 | >= 0, < 3.3.8 | Affected |
Frequently Asked Questions
What is CVE-2026-42855?
CVE-2026-42855 is a high-severity vulnerability affecting espressif arduino-esp32. It was published on May 12, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).
How severe is CVE-2026-42855?
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-42855?
Check the references section for vendor advisories and patches from espressif. Update arduino-esp32 to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-42855?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-42855 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
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