CVE-2026-42855CWE-287

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

High · published May 12, 2026

CVSS v3.1
7.5
EPSS
1%
Percentile
42.4
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS v4.0
Not supplied
EPSS
0.00508 · 42.4th percentile
Weakness
CWE-287 · Improper Authentication
Published
2026-05-12T21:56Z
EPSS history
Timeline
  • 12 MAY 21:56Z
    arduino-esp32: Digest authentication URI mismatch bypass in WebServer allows cross-resource replay attack
    cvelistv5