Encoded URIs can access WEB-INF directory in Eclipse Jetty

Exploitation

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

CVSS

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

EPSS

• CVE-2021-34429: 99.33% estimated exploitation activity in the next 30 days; percentile 99.94 (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.

Description URIs can be crafted using some encoded characters to access the content of the WEB-INF directory and/or bypass some security constraints. This is a variation of the vulnerability reported in CVE-2021-28164/GHSA-v7ff-8wcx-gmc5. Impact The default compliance mode allows requests with URIs that contain a %u002e segment to access protected resources within the WEB-INF directory. For example, a request to /%u002e/WEB-INF/web.xml can retrieve the web.xml file. This can reveal sensitive information regarding the implementation of a web application. Similarly, an encoded null character can prevent correct normalization so that /.%00/WEB-INF/web.xml cal also retrieve the web.xml file. Workarounds Some Jetty rewrite rules can be deployed to rewrite any request containing encoded dot segments or null characters in the raw request URI, to a known not found resource: Analysis Prior to 9.4.37, Jetty was protected from this style of attack by two lines of defense: + URIs were decoded…

Published by the source

19 Jul 2021, 15:15 UTC

Last modified by the source

27 Jan 2023, 05:02 UTC

Source last checked

26 Oct 2026, 16:00 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-vjv5-gp2w-65vm

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2021-34429

Advisory: Encoded URIs can access WEB-INF directory in Eclipse Jetty
IDs: CVE-2021-34429, GHSA-vjv5-gp2w-65vm
Record: https://patchnext.com/advisories/cve-2021-34429 (revision 1, source checked 26 Oct 2026, 16:00 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.eclipse.jetty:jetty-webapp 11.0.6, 10.0.6, 9.4.43. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.eclipse.jetty:jetty-webapp: affected >= 9.4.37, < 9.4.43; >= 10.0.1, < 10.0.6; >= 11.0.1, < 11.0.6; fixed in 10.0.6, 9.4.43, 11.0.6

## Suggested inspection (read-only)
- Maven org.eclipse.jetty:jetty-webapp: check the installed version with your package manager.

## 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 org.eclipse.jetty:jetty-webapp.
- 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://github.com/advisories/GHSA-vjv5-gp2w-65vm (GitHub-reviewed advisory GHSA-vjv5-gp2w-65vm lists affected ranges: Maven org.eclipse.jetty:jetty-webapp >=9.4.37 =10.0.1 =11.0.1 <11.0.6)

Commands are suggestions: review each one before running it.