Vulnerability Details CVE-2026-42855
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.001
EPSS Ranking 15.8%
CVSS Severity
CVSS v3 Score 7.5
Products affected by CVE-2026-42855
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cpe:2.3:a:espressif:arduino-esp32:1.0.0
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cpe:2.3:a:espressif:arduino-esp32:1.0.1
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cpe:2.3:a:espressif:arduino-esp32:1.0.2
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cpe:2.3:a:espressif:arduino-esp32:1.0.3