CVE-2026-42855 PUBLISHED

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

Assigner: GitHub_M
Reserved: 30.04.2026 Published: 12.05.2026 Updated: 12.05.2026

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.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS Score: 7.5

Product Status

Vendor espressif
Product arduino-esp32
Versions
  • Version < 3.3.8 is affected

References

Problem Types

  • CWE-287: Improper Authentication CWE