CVE-2026-42854

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Source

https://cve.org/CVERecord?id=CVE-2026-42854

Import Source

https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-42854.json

JSON Data

https://api.osv.dev/v1/vulns/CVE-2026-42854

Aliases

GHSA-8cmm-3887-r32j

Published

2026-05-12T21:56:33Z

Modified

2026-08-12T03:51:18Z

Severity

9.8 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS Calculator

Summary

arduino-esp32: Stack buffer overflow in WebServer multipart boundary parsing leads to remote crash potential RCE

Details

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 multipart form parser in arduino-esp32 allocates a Variable Length Array (VLA) on the stack whose size is derived from an attacker-controlled HTTP header field (Content-Type: multipart/form-data; boundary=...) without enforcing any length limit. Sending a boundary string longer than ~8000 characters overflows the 8192-byte task stack of the loopTask, causing a crash and potential remote code execution. This vulnerability is fixed in 3.3.8.

Database specific

{
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
        "CWE-121"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42854.json"
}

References

Affected packages

Git / github.com/espressif/arduino-esp32

Affected ranges

Type

GIT

Repo

https://github.com/espressif/arduino-esp32

Events

Introduced

Fixed

b4f85baa2d4a251eb435e0f78fcdda1fb193791f

Database specific

Show details

{
    "cpe": "cpe:2.3:a:espressif:arduino-esp32:*:-:*:*:*:*:*:*",
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "3.3.8"
        }
    ],
    "source": [
        "AFFECTED_FIELD",
        "CPE_RANGE"
    ]
}

Affected versions

1.*

1.0.0

1.0.0-RC0

1.0.0-rc1

1.0.0-rc2

1.0.0-rc3

1.0.0-rc4

1.0.1

1.0.1-rc1

1.0.1-rc2

1.0.1-rc3

1.0.1-rc4

1.0.2

1.0.2-rc1

1.0.2-rc2

1.0.3

1.0.3-rc1

1.0.3-rc2

1.0.3-rc3

1.0.4

1.0.4-rc1

1.0.5

1.0.5-rc1

1.0.5-rc2

1.0.5-rc3

1.0.5-rc4

1.0.5-rc5

1.0.5-rc6

1.0.5-rc7

1.0.6

2.*

2.0.0

2.0.0-alpha1

2.0.0-rc1

2.0.0-rc2

2.0.1

2.0.2

2.0.3

2.0.3-RC1

2.0.4

2.0.5

2.0.6

3.*

3.0.0

3.0.0-alpha1

3.0.0-alpha2

3.0.0-alpha3

3.0.0-rc1

3.0.0-rc2

3.0.0-rc3

3.0.1

3.0.2

3.0.3

3.0.4

3.0.5

3.1.1

3.1.2

3.1.3

3.2.0

3.2.0-RC1

3.2.0-RC2

3.2.1

3.3.0

3.3.1

3.3.2

3.3.3

3.3.4

3.3.5

3.3.6

3.3.6-RC1

3.3.7

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-42854.json"