CVE-2021-22696
Authorization service vulnerable to DDos attacks in Apache CFX
Description
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.
How to fix CVE-2021-22696
To remediate CVE-2021-22696, upgrade the affected package to a fixed version below.
- —upgrade to 3.4.3 or later
- —upgrade to 3.4.3 or later
Is CVE-2021-22696 being exploited?
Low — EPSS is 2.0%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- >= 3.4.0, < 3.4.3
- >= 3.4.0, < 3.4.3
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |