CVE-2026-6402 (GCVE-0-2026-6402)

Vulnerability from cvelistv5 – Published: 2026-05-12 07:45 – Updated: 2026-05-12 13:00
VLAI?
Title
webpack-dev-server vulnerable to cross-origin source code exposure on non-HTTPS origins
Summary
webpack-dev-server versions up to and including 5.2.3 are vulnerable to cross-origin source code exposure when serving over a non-potentially trustworthy origin such as plain HTTP. The previous fix relied on the Sec-Fetch-Mode and Sec-Fetch-Site request headers, which browsers omit for non-trustworthy origins, allowing a malicious site to load the bundled source as a script and read it across origins. Impact: an attacker controlling a website visited by a developer running webpack-dev-server can recover the application source code when the dev server runs over HTTP at a guessable host and port. Chromium based browsers from Chrome 142 onward are not affected due to local network access restrictions. Upgrade to webpack-dev-server 5.2.4 or later, which sets Cross-Origin-Resource-Policy: same-origin on responses.
Severity ?
5.3 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
CWE
  • CWE-749 - Exposed Dangerous Method or Function
Assigner
References
Impacted products
Vendor Product Version
webpack-dev-server webpack-dev-server Affected: 0 , < 5.2.4 (semver)
Unaffected: 5.2.4 (semver)
Create a notification for this product.
Credits
sapphi-red Ulises Gascón Sebastian Beltran Alexander Akait
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-6402",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-12T12:57:17.986993Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-12T13:00:06.847Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:npm/webpack-dev-server",
          "product": "webpack-dev-server",
          "vendor": "webpack-dev-server",
          "versions": [
            {
              "lessThan": "5.2.4",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.2.4",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "sapphi-red"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Ulises Gasc\u00f3n"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Sebastian Beltran"
        },
        {
          "lang": "en",
          "type": "remediation reviewer",
          "value": "Alexander Akait"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "webpack-dev-server versions up to and including 5.2.3 are vulnerable to cross-origin source code exposure when serving over a non-potentially trustworthy origin such as plain HTTP. The previous fix relied on the Sec-Fetch-Mode and Sec-Fetch-Site request headers, which browsers omit for non-trustworthy origins, allowing a malicious site to load the bundled source as a script and read it across origins. Impact: an attacker controlling a website visited by a developer running webpack-dev-server can recover the application source code when the dev server runs over HTTP at a guessable host and port. Chromium based browsers from Chrome 142 onward are not affected due to local network access restrictions. Upgrade to webpack-dev-server 5.2.4 or later, which sets Cross-Origin-Resource-Policy: same-origin on responses."
            }
          ],
          "value": "webpack-dev-server versions up to and including 5.2.3 are vulnerable to cross-origin source code exposure when serving over a non-potentially trustworthy origin such as plain HTTP. The previous fix relied on the Sec-Fetch-Mode and Sec-Fetch-Site request headers, which browsers omit for non-trustworthy origins, allowing a malicious site to load the bundled source as a script and read it across origins. Impact: an attacker controlling a website visited by a developer running webpack-dev-server can recover the application source code when the dev server runs over HTTP at a guessable host and port. Chromium based browsers from Chrome 142 onward are not affected due to local network access restrictions. Upgrade to webpack-dev-server 5.2.4 or later, which sets Cross-Origin-Resource-Policy: same-origin on responses."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-749",
              "description": "CWE-749: Exposed Dangerous Method or Function",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-12T07:45:21.253Z",
        "orgId": "ce714d77-add3-4f53-aff5-83d477b104bb",
        "shortName": "openjs"
      },
      "references": [
        {
          "url": "https://github.com/webpack/webpack-dev-server/security/advisories/GHSA-79cf-xcqc-c78w"
        },
        {
          "url": "https://cna.openjsf.org/security-advisories.html"
        }
      ],
      "title": "webpack-dev-server vulnerable to cross-origin source code exposure on non-HTTPS origins",
      "x_generator": {
        "engine": "cve-kit 1.0.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "ce714d77-add3-4f53-aff5-83d477b104bb",
    "assignerShortName": "openjs",
    "cveId": "CVE-2026-6402",
    "datePublished": "2026-05-12T07:45:21.253Z",
    "dateReserved": "2026-04-15T20:35:29.271Z",
    "dateUpdated": "2026-05-12T13:00:06.847Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-6402",
      "date": "2026-05-18",
      "epss": "0.00033",
      "percentile": "0.09869"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-6402\",\"sourceIdentifier\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"published\":\"2026-05-12T09:16:55.640\",\"lastModified\":\"2026-05-18T15:23:03.800\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"webpack-dev-server versions up to and including 5.2.3 are vulnerable to cross-origin source code exposure when serving over a non-potentially trustworthy origin such as plain HTTP. The previous fix relied on the Sec-Fetch-Mode and Sec-Fetch-Site request headers, which browsers omit for non-trustworthy origins, allowing a malicious site to load the bundled source as a script and read it across origins. Impact: an attacker controlling a website visited by a developer running webpack-dev-server can recover the application source code when the dev server runs over HTTP at a guessable host and port. Chromium based browsers from Chrome 142 onward are not affected due to local network access restrictions. Upgrade to webpack-dev-server 5.2.4 or later, which sets Cross-Origin-Resource-Policy: same-origin on responses.\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N\",\"baseScore\":5.3,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"REQUIRED\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":1.6,\"impactScore\":3.6},{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N\",\"baseScore\":6.5,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"REQUIRED\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":2.8,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-749\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:webpack.js:webpack-dev-server:*:*:*:*:*:*:*:*\",\"versionEndExcluding\":\"5.2.4\",\"matchCriteriaId\":\"F7A95333-66AD-4DB6-993F-079B745E0C59\"}]}]}],\"references\":[{\"url\":\"https://cna.openjsf.org/security-advisories.html\",\"source\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"tags\":[\"Vendor Advisory\"]},{\"url\":\"https://github.com/webpack/webpack-dev-server/security/advisories/GHSA-79cf-xcqc-c78w\",\"source\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"tags\":[\"Mitigation\",\"Vendor Advisory\"]}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-6402\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-05-12T12:57:17.986993Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-05-12T12:58:56.596Z\"}}], \"cna\": {\"title\": \"webpack-dev-server vulnerable to cross-origin source code exposure on non-HTTPS origins\", \"credits\": [{\"lang\": \"en\", \"type\": \"reporter\", \"value\": \"sapphi-red\"}, {\"lang\": \"en\", \"type\": \"remediation developer\", \"value\": \"Ulises Gasc\\u00f3n\"}, {\"lang\": \"en\", \"type\": \"remediation developer\", \"value\": \"Sebastian Beltran\"}, {\"lang\": \"en\", \"type\": \"remediation reviewer\", \"value\": \"Alexander Akait\"}], \"metrics\": [{\"format\": \"CVSS\", \"cvssV3_1\": {\"version\": \"3.1\", \"baseScore\": 5.3, \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}]}], \"affected\": [{\"vendor\": \"webpack-dev-server\", \"product\": \"webpack-dev-server\", \"versions\": [{\"status\": \"affected\", \"version\": \"0\", \"lessThan\": \"5.2.4\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"5.2.4\", \"versionType\": \"semver\"}], \"packageURL\": \"pkg:npm/webpack-dev-server\", \"defaultStatus\": \"unaffected\"}], \"references\": [{\"url\": \"https://github.com/webpack/webpack-dev-server/security/advisories/GHSA-79cf-xcqc-c78w\"}, {\"url\": \"https://cna.openjsf.org/security-advisories.html\"}], \"x_generator\": {\"engine\": \"cve-kit 1.0.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"webpack-dev-server versions up to and including 5.2.3 are vulnerable to cross-origin source code exposure when serving over a non-potentially trustworthy origin such as plain HTTP. The previous fix relied on the Sec-Fetch-Mode and Sec-Fetch-Site request headers, which browsers omit for non-trustworthy origins, allowing a malicious site to load the bundled source as a script and read it across origins. Impact: an attacker controlling a website visited by a developer running webpack-dev-server can recover the application source code when the dev server runs over HTTP at a guessable host and port. Chromium based browsers from Chrome 142 onward are not affected due to local network access restrictions. Upgrade to webpack-dev-server 5.2.4 or later, which sets Cross-Origin-Resource-Policy: same-origin on responses.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"webpack-dev-server versions up to and including 5.2.3 are vulnerable to cross-origin source code exposure when serving over a non-potentially trustworthy origin such as plain HTTP. The previous fix relied on the Sec-Fetch-Mode and Sec-Fetch-Site request headers, which browsers omit for non-trustworthy origins, allowing a malicious site to load the bundled source as a script and read it across origins. Impact: an attacker controlling a website visited by a developer running webpack-dev-server can recover the application source code when the dev server runs over HTTP at a guessable host and port. Chromium based browsers from Chrome 142 onward are not affected due to local network access restrictions. Upgrade to webpack-dev-server 5.2.4 or later, which sets Cross-Origin-Resource-Policy: same-origin on responses.\", \"base64\": false}]}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-749\", \"description\": \"CWE-749: Exposed Dangerous Method or Function\"}]}], \"providerMetadata\": {\"orgId\": \"ce714d77-add3-4f53-aff5-83d477b104bb\", \"shortName\": \"openjs\", \"dateUpdated\": \"2026-05-12T07:45:21.253Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-6402\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-05-12T13:00:06.847Z\", \"dateReserved\": \"2026-04-15T20:35:29.271Z\", \"assignerOrgId\": \"ce714d77-add3-4f53-aff5-83d477b104bb\", \"datePublished\": \"2026-05-12T07:45:21.253Z\", \"assignerShortName\": \"openjs\"}",
      "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.