arduino-esp32: Digest authentication URI mismatch bypass in WebServer allows cross-resource replay attack

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.

Problem type

CWE-287: Improper Authentication

Affected products

espressif

arduino-esp32

< 3.3.8 - AFFECTED

References

https://github.com/espressif/arduino-esp32/security/advisories/GHSA-28hv-fwm3-rpcq

https://github.com/espressif/arduino-esp32/security/advisories/GHSA-28hv-fwm3-rpcq

x_refsource_CONFIRM

JSON source

https://cveawg.mitre.org/api/cve/CVE-2026-42855

Click to expand

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    "assignerShortName": "GitHub_M",
    "dateUpdated": "2026-05-12T21:56:08.490Z",
    "dateReserved": "2026-04-30T16:44:48.379Z",
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      "title": "arduino-esp32: Digest authentication URI mismatch bypass in WebServer allows cross-resource replay attack",
      "descriptions": [
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          "value": "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."
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            "privilegesRequired": "NONE",
            "userInteraction": "NONE",
            "scope": "UNCHANGED",
            "confidentialityImpact": "HIGH",
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