A cross-site scripting (XSS) flaw was found in RESTEasy in versions before 3.11.1.Final and before 4.5.3.Final, where it did not properly handle URL encoding when the RESTEASY003870 exception occurs. An attacker could use this flaw to launch a reflected XSS attack.
An official patch is available. Apply the patch as soon as possible.
CVSS v4.0 Metrics
Exploitability
Attack VectorNetwork
ComplexityLow
RequirementsPresent
PrivilegesNone
User InteractionActive
Threat
Exploit MaturityUnreported
Vulnerable System
ConfidentialityLow
IntegrityLow
AvailabilityNone
Subsequent System
ConfidentialityNone
IntegrityNone
AvailabilityNone
Supplemental
SafetyNegligible
AutomatableYes
RecoveryAutomatic
Value DensityConcentrated
UrgencyMedium
Patch StatusOfficial Patch
Change Log
| Date | Source | Changes | Score |
|---|
| 2026-07-21 | nvd | AV: P→N, AC: H→L, PR: H→N, VC: N→L, VI: N→L | 0.0 → 0.5 |
| 2026-07-21 | nvd | patch: Unavailable→Official Patch | 0.0 → 0.0 |
| 2026-07-21 | cve.org | initial, patch: Unavailable | 0.0 |
Affected Software
| Vendor | Product | Version |
|---|
| n/a | RESTEasy | resteasy 3.11.1.Final, resteasy 4.5.3.Final |
| redhat | fuse | 1.0 |
| redhat | jboss_enterprise_application_platform | All versions |
| redhat | jboss_enterprise_application_platform | 7.3 |
| redhat | jboss_enterprise_application_platform | 7.4 |
| redhat | openshift_application_runtimes | All versions |
| redhat | resteasy | ≥ 4.5.0, < 4.5.3 |
| redhat | resteasy | < 3.11.1 |
Published: 2021-05-27
