CVE-2021-22696 | OAuth 2 authorization service vulnerable to DDos attacks

CXF supports (via JwtRequestCodeFilter) passing OAuth 2 parameters via a JWT token as opposed to query parameters (see: The OAuth 2.0 Authorization Framework: JWT Secured Authorization Request (JAR)). Instead of sending a JWT token as a "request" parameter, the spec also supports specifying a URI from which to retrieve a JWT token from via the "request_uri" parameter. CXF was not validating the "request_uri" parameter (apart from ensuring it uses "https) and was making a REST request to the parameter in the request to retrieve a token. This means that CXF was vulnerable to DDos attacks on the authorization server, as specified in section 10.4.1 of the spec. This issue affects Apache CXF versions prior to 3.4.3; Apache CXF versions prior to 3.3.10.

Published: 2021-04-02 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-22696 is rated Moderate Risk (54/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.97%). Review affected assets and schedule 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-2021-22696

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 2025-11-21 8.11% 1.97% -6.14%
2 2025-11-18 1.97% 8.11% +6.14%
3 2025-11-15 — 1.97% —

Full EPSS history (20 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-22696

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H 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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P 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:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-22696

GitHub Security Advisory for CVE-2021-22696

GHSA-7q4h-pj78-j7vg · Severity: high · Ecosystem: maven — Authorization service vulnerable to DDos attacks in Apache CFX

OS Trackers for CVE-2021-22696

vendor priority summary link
redhat medium — https://access.redhat.com/security/cve/CVE-2021-22696

Affected software / configurations for CVE-2021-22696

Vendor Product Version Raw CPE
apache cxf < 3.3.10 cpe:2.3:a:apache:cxf:*:*:*:*:*:*:*:*
apache cxf >= 3.4.0, < 3.4.3 cpe:2.3:a:apache:cxf:*:*:*:*:*:*:*:*
oracle business_intelligence 5.5.0.0.0 cpe:2.3:a:oracle:business_intelligence:5.5.0.0.0:*:*:*:enterprise:*:*:*
oracle business_intelligence 5.9.0.0.0 cpe:2.3:a:oracle:business_intelligence:5.9.0.0.0:*:*:*:enterprise:*:*:*
oracle business_intelligence 12.2.1.3.0 cpe:2.3:a:oracle:business_intelligence:12.2.1.3.0:*:*:*:enterprise:*:*:*
oracle business_intelligence 12.2.1.4.0 cpe:2.3:a:oracle:business_intelligence:12.2.1.4.0:*:*:*:enterprise:*:*:*
oracle communications_diameter_intelligence_hub >= 8.0.0, <= 8.1.0 cpe:2.3:a:oracle:communications_diameter_intelligence_hub:*:*:*:*:*:*:*:*
oracle communications_diameter_intelligence_hub >= 8.2.0, <= 8.2.3 cpe:2.3:a:oracle:communications_diameter_intelligence_hub:*:*:*:*:*:*:*:*
oracle communications_element_manager 8.2.2 cpe:2.3:a:oracle:communications_element_manager:8.2.2:*:*:*:*:*:*:*
oracle communications_session_report_manager >= 8.0.0, <= 8.2.4.0 cpe:2.3:a:oracle:communications_session_report_manager:*:*:*:*:*:*:*:*
oracle communications_session_route_manager >= 8.0.0, <= 8.2.4 cpe:2.3:a:oracle:communications_session_route_manager:*:*:*:*:*:*:*:*

References for CVE-2021-22696

URL Tags
http://www.openwall.com/lists/oss-security/2021/04/02/2 Mailing List Third Party Advisory
https://cxf.apache.org/security-advisories.data/CVE-2021-22696.txt.asc Vendor Advisory
https://lists.apache.org/thread.html/r6445001cc5f9a2bb1e6316993753306e054bdd1d702656b7cbe59045%40%3Cannounce.apache.org%3E
https://lists.apache.org/thread.html/r8651c06212c56294a1c0ea61a5ad7790c06502209c03f05c0c7c9914%40%3Cdev.cxf.apache.org%3E
https://lists.apache.org/thread.html/r8651c06212c56294a1c0ea61a5ad7790c06502209c03f05c0c7c9914%40%3Cusers.cxf.apache.org%3E
https://lists.apache.org/thread.html/rec7160382badd3ef4ad017a22f64a266c7188b9ba71394f0d321e2d4%40%3Ccommits.cxf.apache.org%3E
https://lists.apache.org/thread.html/rfb87e0bf3995e7d560afeed750fac9329ff5f1ad49da365129b7f89e%40%3Ccommits.cxf.apache.org%3E
https://www.oracle.com/security-alerts/cpuapr2022.html Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.html Patch Third Party Advisory
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