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TI-2026-31062 Aliases CVE-2026-42855

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

Priority LOW 39CWE-287Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
High · None · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-287.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00351 28th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed arduino-esp32 (espressif): 3.3.8

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
espressifarduino-esp32before 3.3.83.3.8Patch availableCNA
  • arduino-esp32 Vendorespressif Affected before 3.3.8 Fixed in 3.3.8 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:espressif:arduino-esp32:*:-:*:*:*:*:*:*before 3.3.8Vulnerableespressif
  • cpe:2.3:a:espressif:arduino-esp32:*:-:*:*:*:*:*:* Versions before 3.3.8 Vulnerable ·espressif

Remediation

  • Fix · CNA arduino-esp32 (espressif) Fixed in 3.3.8

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-42855

References

Exploit 1

  • TI-2026-31061 arduino-esp32: Stack buffer overflow in WebServer multipart boundary parsing leads to remote crash potential RCE CVSS 3.1CRITICAL 9.8
  • TI-2026-30028 Improper validation of NBNS name_len in arduino-esp32 NetBIOS leads to memory corruption CVSS 3.1HIGH 8.8
  • TI-2019-09398 The EAP peer implementation in Espressif ESP-IDF 2.0.0 through 4.0.0 and… CVSS 3.0MEDIUM 6.5

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences