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MEDIUM severity

CVE-2021-20293 — resteasy-bom

MEDIUM

CVE-2021-20293 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in org.jboss.resteasy:resteasy-bom. The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.

Cross-Site Scripting

Also known asGHSA-5h26-c766-g93v
Published
Updated
Affected
2 pkgs
Patched
See advisory
Exploits
None indexed
Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
0.9%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs59th percentile — riskier than 59% of all scored CVEsHighest risk
0.00%0.45%0.90%1.36%0.1%0.9%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected
☕org.jboss.resteasy:resteasy-bom☕org.jboss.resteasy:resteasy-core

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

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.

Affected Packages

2 total
EcosystemPackageVulnerable rangeFix
☕Mavenorg.jboss.resteasy:resteasy-bomall versionsNo fix
☕Mavenorg.jboss.resteasy:resteasy-coreall versionsNo fix

Affected Products

2 products · 2 configurations
Application
oncommand insightnetapp
all
Application
resteasyredhat
≤ 4.6.0
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.jboss.resteasy:resteasy-bom, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Remediation status

    The records we use list no patched version of org.jboss.resteasy:resteasy-bom for CVE-2021-20293. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.

  3. Mitigate without a patch

    Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate
ProductFixed inAdvisory
RHINT Camel-K 1.6.4see advisoryRHSA-2022:1029
RHINT Service Registry 2.0.2 GAresteasy-coreRHSA-2021:4100

Frequently Asked Questions

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.
O3 Security · Impact-Aware SCA

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CVE-2021-20293: resteasy-bom: Cross-Site Scripting