Vulnerability details
CVE-2026-42855
espressif arduino-esp32
arduino-esp32: Digest authentication URI mismatch bypass in WebServer allows cross-resource replay attack
CVSS 3.1
7.5High
Official 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.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 7.5High | 3.1 | CVEProject cvelistV5 (CNA) (GitHub_M) | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| espressif | arduino-esp32 | < 3.3.8 | CVEProject cvelistV5 (CNA) |
References and advisories
1
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Details
- Published
- 2026-05-13
- Last updated
- 2026-05-13
- State
- Published
- Assigner (CNA)
- GitHub_M
Exploit prediction (EPSS)
0.35%
Probability of exploitation in 30 days
28.9%
Percentile (among all CVEs)
SSVC assessment (CISA)
- Automatable
- Yes
- Exploitation
- None
- Technical impact
- Partial
Weaknesses (CWE)
- CWE-287Improper Authentication