zlib 1.2.11 through 1.3.2 contains a heap buffer overflow: after an underlying write() fails, gz_write() returns without resetting strm.next_in, leaving it pointed at the caller's buffer. A later gz* write call then derives a position from the stale pointer and writes past a heap allocation; any write() failure reaches it, including EPIPE on a blocking descriptor, and in versions before 1.3.1.2 the failed write must be followed by a gzclearerr() call.
Advisories
Source ID Title
Github GHSA Github GHSA GHSA-g84c-rxfj-3j2c webpack-dev-middleware vulnerable to Path Traversal via non-slash-terminated publicPath
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Thu, 01 Oct 2026 12:30:00 +0000


Thu, 01 Oct 2026 11:30:00 +0000

Type Values Removed Values Added
Description webpack-dev-middleware 5.3.4, 6.1.2 through 6.1.3, 7.1.0 before 7.4.6, and 8.0.0 before 8.3.0 contains a path traversal vulnerability in getFilenameFromUrl that bypasses the fix for CVE-2024-29180: a publicPath without a trailing slash is matched by string prefix, and the '..' guard runs before that prefix is stripped. Unauthenticated attackers can request a path such as /assets../secret to read files one directory above the output directory when the middleware serves from the physical filesystem through writeToDisk or a custom outputFileSystem. zlib 1.2.11 through 1.3.2 contains a heap buffer overflow: after an underlying write() fails, gz_write() returns without resetting strm.next_in, leaving it pointed at the caller's buffer. A later gz* write call then derives a position from the stale pointer and writes past a heap allocation; any write() failure reaches it, including EPIPE on a blocking descriptor, and in versions before 1.3.1.2 the failed write must be followed by a gzclearerr() call.
Title webpack-dev-middleware before 7.4.6 and 8.3.0 Path Traversal via Non-Slash-Terminated publicPath zlib 1.2.11 through 1.3.2 Heap Buffer Overflow via Stale gzwrite Pointer After Failed Write
First Time appeared Zlib
Zlib zlib
Weaknesses CWE-787
CPEs cpe:2.3:a:webpack.js:webpack-dev-middleware:*:*:*:*:*:*:*:* cpe:2.3:a:zlib:zlib:*:*:*:*:*:*:*:*
Vendors & Products Zlib
Zlib zlib
References
Metrics cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N'}

cvssV4_0

{'score': 8.3, 'vector': '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'}

cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H'}

cvssV4_0

{'score': 8.3, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N'}


Thu, 01 Oct 2026 11:00:00 +0000

Type Values Removed Values Added
Description 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. webpack-dev-middleware 5.3.4, 6.1.2 through 6.1.3, 7.1.0 before 7.4.6, and 8.0.0 before 8.3.0 contains a path traversal vulnerability in getFilenameFromUrl that bypasses the fix for CVE-2024-29180: a publicPath without a trailing slash is matched by string prefix, and the '..' guard runs before that prefix is stripped. Unauthenticated attackers can request a path such as /assets../secret to read files one directory above the output directory when the middleware serves from the physical filesystem through writeToDisk or a custom outputFileSystem.
Title webpack-dev-middleware Path Traversal via Offset Slice on a Non-Slash-Terminated publicPath webpack-dev-middleware before 7.4.6 and 8.3.0 Path Traversal via Non-Slash-Terminated publicPath
References

Thu, 27 Aug 2026 18:00:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Important


Wed, 26 Aug 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 24 Aug 2026 13:30:00 +0000

Type Values Removed Values Added
Description 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.
Title webpack-dev-middleware Path Traversal via Offset Slice on a Non-Slash-Terminated publicPath
First Time appeared Webpack.js
Webpack.js webpack-dev-middleware
Weaknesses CWE-22
CPEs cpe:2.3:a:webpack.js:webpack-dev-middleware:*:*:*:*:*:*:*:*
Vendors & Products Webpack.js
Webpack.js webpack-dev-middleware
References
Metrics cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N'}

cvssV4_0

{'score': 8.3, 'vector': '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'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-01T11:03:59.221Z

Reserved: 2026-08-19T20:34:19.724Z

Link: CVE-2026-76844

cve-icon Vulnrichment

Updated: 2026-08-26T18:22:40.939Z

cve-icon NVD

Status : Deferred

Published: 2026-08-24T14:17:02.250

Modified: 2026-10-01T12:17:16.387

Link: CVE-2026-76844

cve-icon Redhat

Severity : Important

Publid Date: 2026-08-24T13:12:01Z

Links: CVE-2026-76844 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-01T22:45:13Z

Weaknesses