WsgiDAV encoded dot segments can escape filesystem share roots

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.1 · CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L

EPSS

• CVE-2026-48099: 0.33% estimated exploitation activity in the next 30 days; percentile 26.31 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact WsgiDAV 4.3.3 can allow a WebDAV request path containing an encoded parent-directory segment to escape the configured filesystem share root in a specific path layout. Patches The issue is fixed with version 4.3.4. Preconditions The practical impact depends on the deployment. The deployment uses a filesystem-backed WsgiDAV share. The attacker can send WebDAV requests accepted by that share. This may be an anonymous share or an authenticated WebDAV user. This is not an authentication bypass. Details The issue is in FilesystemProvider.loctofilepath(). The method builds a candidate path with os.path.abspath(os.path.join(rootpath, pathparts)), then checks containment with filepath.startswith(rootpath). This is not path-boundary aware. For example, if the configured share root is /tmp/share, a resolved sibling path such as /tmp/shareevil/secret.txt still starts with the string /tmp/share. In a local proof, this allowed GET, PUT, and DELETE requests to operate on files outside the…

Published by the source

11 Jun 2026, 20:28 UTC

Last modified by the source

13 Jul 2026, 16:43 UTC

Source last checked

26 Oct 2026, 13:45 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-wxq4-cc2q-338q

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-wxq4-cc2q-338q

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# Patch Next advisory brief: CVE-2026-48099

Advisory: WsgiDAV encoded dot segments can escape filesystem share roots
IDs: CVE-2026-48099, GHSA-wxq4-cc2q-338q
Record: https://patchnext.com/advisories/cve-2026-48099 (revision 2, source checked 26 Oct 2026, 13:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: wsgidav 4.3.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI wsgidav: affected <= 4.3.3; fixed in 4.3.4

## Suggested inspection (read-only)
- `python -m pip show wsgidav`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on wsgidav.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-wxq4-cc2q-338q (OSV record GHSA-wxq4-cc2q-338q lists affected ranges: PyPI wsgidav >=0 <4.3.4 (fixed))
- Verified: https://github.com/advisories/GHSA-wxq4-cc2q-338q (GitHub-reviewed advisory GHSA-wxq4-cc2q-338q lists affected ranges: PyPI wsgidav >=0 <=4.3.3)

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