CVE-2026-42855 (GCVE-0-2026-42855)

Vulnerability from cvelistv5 – Published: 2026-05-12 21:56 – Updated: 2026-05-13 15:36
VLAI?
Title
arduino-esp32: Digest authentication URI mismatch bypass in WebServer allows cross-resource replay attack
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.
Severity ?
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CWE
  • CWE-287 - Improper Authentication
Assigner
References
Impacted products
Vendor Product Version
espressif arduino-esp32 Affected: < 3.3.8
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-42855",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-13T15:32:50.254940Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-13T15:36:54.428Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "arduino-esp32",
          "vendor": "espressif",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 3.3.8"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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\u0027s 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": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-287",
              "description": "CWE-287: Improper Authentication",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-12T21:56:08.490Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/espressif/arduino-esp32/security/advisories/GHSA-28hv-fwm3-rpcq",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/espressif/arduino-esp32/security/advisories/GHSA-28hv-fwm3-rpcq"
        }
      ],
      "source": {
        "advisory": "GHSA-28hv-fwm3-rpcq",
        "discovery": "UNKNOWN"
      },
      "title": "arduino-esp32: Digest authentication URI mismatch bypass in WebServer allows cross-resource replay attack"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-42855",
    "datePublished": "2026-05-12T21:56:08.490Z",
    "dateReserved": "2026-04-30T16:44:48.379Z",
    "dateUpdated": "2026-05-13T15:36:54.428Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-42855",
      "date": "2026-05-17",
      "epss": "0.0004",
      "percentile": "0.12042"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-42855\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-05-12T22:16:35.067\",\"lastModified\":\"2026-05-15T15:54:16.923\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"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\u0027s 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\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-287\"}]},{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"NVD-CWE-noinfo\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:espressif:arduino-esp32:*:-:*:*:*:*:*:*\",\"versionEndExcluding\":\"3.3.8\",\"matchCriteriaId\":\"308785AC-A885-47B5-9131-64AE662B6525\"}]}]}],\"references\":[{\"url\":\"https://github.com/espressif/arduino-esp32/security/advisories/GHSA-28hv-fwm3-rpcq\",\"source\":\"security-advisories@github.com\",\"tags\":[\"Exploit\",\"Vendor Advisory\"]}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-42855\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-05-13T15:32:50.254940Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-05-13T15:32:53.132Z\"}}], \"cna\": {\"title\": \"arduino-esp32: Digest authentication URI mismatch bypass in WebServer allows cross-resource replay attack\", \"source\": {\"advisory\": \"GHSA-28hv-fwm3-rpcq\", \"discovery\": \"UNKNOWN\"}, \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 7.5, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"NONE\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"HIGH\"}}], \"affected\": [{\"vendor\": \"espressif\", \"product\": \"arduino-esp32\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003c 3.3.8\"}]}], \"references\": [{\"url\": \"https://github.com/espressif/arduino-esp32/security/advisories/GHSA-28hv-fwm3-rpcq\", \"name\": \"https://github.com/espressif/arduino-esp32/security/advisories/GHSA-28hv-fwm3-rpcq\", \"tags\": [\"x_refsource_CONFIRM\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"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\u0027s 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.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-287\", \"description\": \"CWE-287: Improper Authentication\"}]}], \"providerMetadata\": {\"orgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"shortName\": \"GitHub_M\", \"dateUpdated\": \"2026-05-12T21:56:08.490Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-42855\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-05-13T15:36:54.428Z\", \"dateReserved\": \"2026-04-30T16:44:48.379Z\", \"assignerOrgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"datePublished\": \"2026-05-12T21:56:08.490Z\", \"assignerShortName\": \"GitHub_M\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.