{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-76844", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "state": "PUBLISHED", "assignerShortName": "VulnCheck", "dateReserved": "2026-08-19T20:34:19.724Z", "datePublished": "2026-08-24T13:12:01.148Z", "dateUpdated": "2026-08-24T13:12:01.148Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-08-24T13:12:01.148Z" }, "datePublic": "2026-08-20T00:00:00.000Z", "title": "webpack-dev-middleware Path Traversal via Offset Slice on a Non-Slash-Terminated publicPath", "descriptions": [ { "lang": "en", "value": "webpack-dev-middleware resolves a request to a local file in getFilenameFromUrl by testing the request pathname against a traversal guard and then slicing it at a fixed character offset. The guard, UP_PATH_REGEXP applied to path.normalize(`./${pathname}`), only matches \"..\" that stands as a whole path segment, while the containment test is the string comparison pathname.startsWith(publicPathPathname) and the file path is built as path.join(outputPath, pathname.slice(publicPathPathname.length)). When the configured publicPath has no trailing slash, a request such as GET /assets../.env against publicPath /assets yields the pathname /assets../.env, whose only dot-dot sits inside the segment \"assets..\" and so passes the guard, but the offset slice cuts within that segment and hands \"../.env\" to path.join, resolving one directory above outputPath. Reading a file from that path requires the middleware to be backed by the physical filesystem, which happens when writeToDisk is true or a custom outputFileSystem is supplied, since the default memfs volume holds only build output. Traversal depth is limited to a single directory because a separately delimited dot-dot segment is collapsed during URL parsing before the guard runs. The default publicPath value of \"auto\" resolves to \"/\" and is not affected. This is an incomplete fix for CVE-2024-29180: the guard and offset slice were introduced by that fix and are present in every release from 5.3.4, 6.1.2 and 7.1.0 onward." } ], "problemTypes": [ { "descriptions": [ { "lang": "en", "cweId": "CWE-22", "description": "Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')", "type": "CWE" } ] } ], "affected": [ { "vendor": "webpack", "product": "webpack-dev-middleware", "collectionURL": "https://www.npmjs.com/package/webpack-dev-middleware", "packageName": "webpack-dev-middleware", "packageURL": "pkg:npm/webpack-dev-middleware", "defaultStatus": "unaffected", "versions": [ { "version": "5.3.4", "status": "affected", "versionType": "semver", "lessThanOrEqual": "5.3.4" }, { "version": "6.1.2", "lessThanOrEqual": "6.1.3", "status": "affected", "versionType": "semver" }, { "version": "7.1.0", "lessThanOrEqual": "7.4.5", "status": "affected", "versionType": "semver" }, { "version": "8.0.0", "lessThanOrEqual": "8.1.1", "status": "affected", "versionType": "semver" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:a:webpack.js:webpack-dev-middleware:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3.4", "versionEndIncluding": "5.3.4" }, { "vulnerable": true, "criteria": "cpe:2.3:a:webpack.js:webpack-dev-middleware:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1.2", "versionEndIncluding": "6.1.3" }, { "vulnerable": true, "criteria": "cpe:2.3:a:webpack.js:webpack-dev-middleware:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.1.0", "versionEndIncluding": "7.4.5" }, { "vulnerable": true, "criteria": "cpe:2.3:a:webpack.js:webpack-dev-middleware:*:*:*:*:*:*:*:*", "versionStartIncluding": "8.0.0", "versionEndIncluding": "8.1.1" } ] } ] } ], "metrics": [ { "format": "CVSS", "cvssV4_0": { "version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N", "baseScore": 8.3, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "PASSIVE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "HIGH", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE" } }, { "format": "CVSS", "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N", "baseScore": 7.4, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "NONE" } } ], "references": [ { "url": "https://github.com/webpack/webpack-dev-middleware", "tags": [ "product" ] }, { "url": "https://github.com/webpack/webpack-dev-middleware/blob/v8.1.1/src/middleware.js", "tags": [ "technical-description" ] }, { "url": "https://github.com/advisories/GHSA-wr3j-pwj9-hqq6", "tags": [ "related" ] }, { "name": "VulnCheck Advisory: webpack-dev-middleware Path Traversal via Offset Slice on a Non-Slash-Terminated publicPath", "tags": [ "third-party-advisory" ], "url": "https://www.vulncheck.com/advisories/webpack-dev-middleware-path-traversal-via-offset-slice-on-a-non-slash-terminated-publicpath" } ], "credits": [ { "lang": "en", "value": "Muhammad Sobirov", "type": "finder" } ], "x_generator": { "engine": "vulncheck-endgame" } } } }