CVE-2021-28169
MediumExploitedFor Eclipse Jetty versions <= 9.4.40, <= 10.0.2, <= 11.0.2, it is possible for requests to the ConcatServlet with a doubly encoded path to access protected resources within the WEB-INF directory.
Published Oct 21, 2021 · Updated Sep 10, 2026 · Also known as DEBIAN-CVE-2021-28169, DLA-2688-1, GHSA-gwcr-j4wh-j3cq, TR-21-0848, TR-21-0859, UBUNTU-CVE-2021-28169
Key Facts
Patch immediately- CVE-2021-28169 is a medium-severity vulnerability (CVSS 5.3 v3.1) affecting Jetty (Eclipse), Active Iq Unified Manager (Netapp), Hci (Netapp) and 22 more products.
- It is exploited in the wild, listed in Industry KEV feed since Aug 19, 2022. No public exploit code is known.
- EPSS estimates a 78% probability of exploitation in the next 30 days.
- Fixed versions are available, including Jetty 9.4.41, jenkins 0:2.289.3.1630554997-1.el8, jetty-annotations 9.0.3-8.amzn2.0.1.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
5.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
EPSS (30-day exploit likelihood)
78%
Higher than 99.5% of all scored CVEs
Exploited in the wild
Yes
1 catalog listing
Public exploit code
None known
Get the full CVE-2021-28169 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
Description
For Eclipse Jetty versions <= 9.4.40, <= 10.0.2, <= 11.0.2, it is possible for requests to the ConcatServlet with a doubly encoded path to access protected resources within the WEB-INF directory. For example a request to /concat?/%2557EB-INF/web.xml can retrieve the web.xml file. This can reveal sensitive information regarding the implementation of a web application.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| Industry KEV feed | Aug 19, 2022 | n/a | Not reported |
Required action: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.
Affected Products
160 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| JettyEclipse | >= unspecified | 9.4.41 |
| Active Iq Unified ManagerNetapp | See advisory | n/a |
| HciNetapp | See advisory | n/a |
| Management Services For Element SoftwareNetapp | See advisory | n/a |
| Snap Creator FrameworkNetapp | See advisory | n/a |
Patched Releases
Jetty
9.4.41
jenkins
0:2.289.3.1630554997-1.el8
jetty-annotations
9.0.3-8.amzn2.0.1, 9.4.42-3.9.1, 9.4.43-1.2
jetty-ant
9.0.3-8.amzn2.0.1, 9.4.43-1.2
jetty-cdi
9.4.43-1.2
jetty-client
9.0.3-8.amzn2.0.1, 9.4.42-3.9.1, 9.4.43-1.2
jetty-continuation
9.0.3-8.amzn2.0.1, 9.4.42-3.9.1, 9.4.43-1.2
jetty-deploy
9.0.3-8.amzn2.0.1, 9.4.43-1.2
jetty-fcgi
9.4.43-1.2
jetty-http
9.0.3-8.amzn2.0.1, 9.4.42-3.9.1, 9.4.43-1.2
jetty-http-spi
9.4.43-1.2
jetty-io
9.0.3-8.amzn2.0.1, 9.4.42-3.9.1, 9.4.43-1.2
jetty-jaas
9.0.3-8.amzn2.0.1, 9.4.42-3.9.1, 9.4.43-1.2
jetty-jaspi
9.0.3-8.amzn2.0.1
jetty-javadoc
9.0.3-8.amzn2.0.1
jetty-javax-websocket-client-impl
9.4.42-3.9.1
jetty-javax-websocket-server-impl
9.4.42-3.9.1
jetty-jmx
9.0.3-8.amzn2.0.1, 9.4.42-3.9.1, 9.4.43-1.2
jetty-jndi
9.0.3-8.amzn2.0.1, 9.4.42-3.9.1, 9.4.43-1.2
jetty-jsp
9.0.3-8.amzn2.0.1, 9.4.42-3.9.1, 9.4.43-1.2
jetty-jspc-maven-plugin
9.0.3-8.amzn2.0.1
jetty-maven-plugin
9.0.3-8.amzn2.0.1
jetty-minimal
9.4.42-3.9.1
jetty-minimal-javadoc
9.4.42-3.9.1, 9.4.43-1.2
jetty-monitor
9.0.3-8.amzn2.0.1
Timeline
Publicly disclosed
Oct 21, 2021
Added to Industry KEV feed
Aug 19, 2022
Last updated
Sep 10, 2026
Weakness Type
- CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
References
- advisoryhttp://access.redhat.com/errata/RHSA-2021:3758
- advisoryhttp://access.redhat.com/errata/RHSA-2021:3841
- advisoryhttp://access.redhat.com/errata/RHSA-2021:3856
- advisoryRHSA-2021:3225
- advisoryRHSA-2021:3700
FAQ
Common Questions.
For Eclipse Jetty versions <= 9.4.40, <= 10.0.2, <= 11.0.2, it is possible for requests to the ConcatServlet with a doubly encoded path to access protected resources within the WEB-INF directory.
Affected: Jetty (Eclipse) versions >= unspecified; Active Iq Unified Manager (Netapp); Hci (Netapp), among others. The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed since Aug 19, 2022.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including Jetty 9.4.41, jenkins 0:2.289.3.1630554997-1.el8, jetty-annotations 9.0.3-8.amzn2.0.1.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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