CVE-2021-28169

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.

Published: 2021-06-09 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-28169 is rated Moderate Risk (51/100): CVSS Medium severity, with high exploitation likelihood (EPSS 78.48%, 100th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-28169

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 90.26% 78.48% -11.78%
2 2026-03-15 89.24% 90.26% +1.01%
3 2026-03-10 — 89.24% —

Full EPSS history (53 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-28169

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 1.4 [email protected]
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 1.4 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-28169

GitHub Security Advisory for CVE-2021-28169

GHSA-gwcr-j4wh-j3cq · Severity: medium · Ecosystem: maven — Jetty Utility Servlets ConcatServlet Double Decoding Information Disclosure Vulnerability

OS Trackers for CVE-2021-28169

vendor priority summary link
debian not yet assigned CVE-2021-28169 not yet assigned priority: Debian including 1 source packages (jetty9), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-28169
redhat medium — https://access.redhat.com/security/cve/CVE-2021-28169
suse medium CVE-2021-28169 severity moderate: SUSE including 57 source package names (jetty-annotations-9.4.42-3.9.1, jetty-annotations-9.4.43-1.2, …), 185 product×package rows across 14 product lines (SUSE Linux Enterprise Module for Development Tools 15 SP2, SUSE Linux Enterprise Module for Development Tools 15 SP3, … (14 product lines)): Fixed 185. https://www.suse.com/security/cve/CVE-2021-28169/
ubuntu medium CVE-2021-28169 medium priority: Ubuntu including 3 source packages (jetty, jetty8, jetty9), 48 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 27, ignored 6, needs-triage 6, not-affected 5, needed 3, released 1. https://ubuntu.com/security/CVE-2021-28169

Affected software / configurations for CVE-2021-28169

Vendor Product Version Raw CPE
eclipse jetty < 9.4.41 cpe:2.3:a:eclipse:jetty:*:*:*:*:*:*:*:*
eclipse jetty >= 10.0.0, < 10.0.3 cpe:2.3:a:eclipse:jetty:*:*:*:*:*:*:*:*
eclipse jetty >= 11.0.0, < 11.0.3 cpe:2.3:a:eclipse:jetty:*:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
oracle communications_cloud_native_core_policy 1.14.0 cpe:2.3:a:oracle:communications_cloud_native_core_policy:1.14.0:*:*:*:*:*:*:*
oracle rest_data_services < 21.3 cpe:2.3:a:oracle:rest_data_services:*:*:*:*:-:*:*:*
netapp active_iq_unified_manager — cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:linux:*:*
netapp active_iq_unified_manager — cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:windows:*:*
netapp hci — cpe:2.3:a:netapp:hci:-:*:*:*:*:*:*:*
netapp management_services_for_element_software — cpe:2.3:a:netapp:management_services_for_element_software:-:*:*:*:*:*:*:*
netapp snap_creator_framework — cpe:2.3:a:netapp:snap_creator_framework:-:*:*:*:*:*:*:*

References for CVE-2021-28169

URL Tags
https://github.com/eclipse/jetty.project/security/advisories/GHSA-gwcr-j4wh-j3cq Third Party Advisory
https://lists.apache.org/thread.html/r04a4b4553a23aff26f42635a6ae388c3b162aab30a88d12e59d05168%40%3Cjira.kafka.apache.org%3E
https://lists.apache.org/thread.html/r234f6452297065636356f43654cdacef565b8f9ceb0e0c07ffb8c73b%40%3Cdev.kafka.apache.org%3E
https://lists.apache.org/thread.html/r2721aba31a8562639c4b937150897e24f78f747cdbda8641c0f659fe%40%3Cusers.kafka.apache.org%3E
https://lists.apache.org/thread.html/r284de9c5399486dfff12ab9e7323ca720dd7019a9a3e11c8510a7140%40%3Cjira.kafka.apache.org%3E
https://lists.apache.org/thread.html/r29678972c3f8164b151fd7a5802785d402e530c09870a82ffc7681a4%40%3Cdev.kafka.apache.org%3E
https://lists.apache.org/thread.html/r32b0b640ad2be3b858f0af51c68a7d5c5a66a462c8bbb93699825cd3%40%3Cissues.zookeeper.apache.org%3E
https://lists.apache.org/thread.html/r33eb06b05afbc7df28d31055cae0cb3fd36cab808c884bf6d680bea5%40%3Cdev.zookeeper.apache.org%3E
https://lists.apache.org/thread.html/r67c4f90658fde875521c949448c54c98517beecdc7f618f902c620ec%40%3Cissues.zookeeper.apache.org%3E
https://lists.apache.org/thread.html/r8a1a332899a1f92c8118b0895b144b27a78e3f25b9d58a34dd5eb084%40%3Cnotifications.zookeeper.apache.org%3E
https://lists.apache.org/thread.html/r91e34ff61aff8fd25a3f2a21539597c6ef7589a31c199b0a9546477c%40%3Cjira.kafka.apache.org%3E
https://lists.apache.org/thread.html/rb1292d30462b9baedea7c5d9594fc75990d9aa0ec223b48054ca9c25%40%3Cjira.kafka.apache.org%3E
https://lists.apache.org/thread.html/rbefa055282d52d6b58d29a79fbb0be65ab0a38d25f00bd29eaf5e6fd%40%3Cnotifications.zookeeper.apache.org%3E
https://lists.apache.org/thread.html/rd5b52362f5edf98e0dcab6541a381f571cccc05ad9188e793af688f3%40%3Cjira.kafka.apache.org%3E
https://lists.apache.org/thread.html/rddbb4f8d5db23265bb63d14ef4b3723b438abc1589f877db11d35450%40%3Cissues.zookeeper.apache.org%3E
https://lists.apache.org/thread.html/ref1c161a1621504e673f9197b49e6efe5a33ce3f0e6d8f1f804fc695%40%3Cjira.kafka.apache.org%3E
https://lists.apache.org/thread.html/rf36f1114e84a3379b20587063686148e2d5a39abc0b8a66ff2a9087a%40%3Cissues.zookeeper.apache.org%3E
https://lists.apache.org/thread.html/rfff6ff8ffb31e8a32619c79774def44b6ffbb037c128c5ad3eab7171%40%3Cissues.zookeeper.apache.org%3E
https://lists.debian.org/debian-lts-announce/2021/06/msg00017.html Mailing List Third Party Advisory
https://security.netapp.com/advisory/ntap-20210727-0009/ Third Party Advisory
https://www.debian.org/security/2021/dsa-4949 Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.html Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.html Patch Third Party Advisory
cvelogic Threat Intelligence