How severe is CVE-2021-28169?

CVE-2021-28169 has a CVSS score of 5.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-28169?

CVE-2021-28169 affects the following packages: org.eclipse.jetty:jetty-servlets (Maven), org.eclipse.jetty:jetty-servlets (Maven), org.eclipse.jetty:jetty-servlets (Maven). Ecosystems affected: Maven.

How do I fix CVE-2021-28169?

Update org.eclipse.jetty:jetty-servlets to version 9.4.41 or later. Run your dependency manager's update command and verify no transitive dependencies pin the vulnerable version. Use O3 Security's SCA scanner to confirm the fix is applied across your entire dependency tree.

Is CVE-2021-28169 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-28169 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-28169?

CVE-2021-28169 has an EPSS (Exploit Prediction Scoring System) score of 90.3%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

What type of vulnerability is CVE-2021-28169?

CVE-2021-28169 is classified as Information Exposure (CWE-200). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Is there exploit tooling available for CVE-2021-28169?

A Nuclei detection template exists for CVE-2021-28169, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2021-28169 published, and has it been updated?

CVE-2021-28169 was published on June 9, 2021 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕ Maven

CVE-2021-28169

MEDIUM

Jetty Utility Servlets ConcatServlet Double Decoding Information Disclosure Vulnerability

Also known asGHSA-gwcr-j4wh-j3cq

Published

Jun 9, 2021

Updated

Apr 10, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

90.3%probability of exploitation in next 30 days

Very High Risk100th percentile0.00%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

3 pkgs affected

☕org.eclipse.jetty:jetty-servlets☕org.eclipse.jetty:jetty-servlets☕org.eclipse.jetty:jetty-servlets

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

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.

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.eclipse.jetty:jetty-servlets`	all versions	9.4.41
☕Maven	`org.eclipse.jetty:jetty-servlets`	≥ 10.0.0&&< 10.0.3	10.0.3
☕Maven	`org.eclipse.jetty:jetty-servlets`	≥ 11.0.0&&< 11.0.3	11.0.3

Frequently Asked 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. 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.

O3 Security · Impact-Aware SCA

Is CVE-2021-28169 in your stack?

O3 detects CVE-2021-28169 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my stack How O3 SCA works

CVSS Score

5.3/10

CVSS v3 base score

Vector breakdown

AV:Attack Vector

Network

AC:Attack Complexity

Low

PR:Privileges Required

None

UI:User Interaction