EUVD-2026-81675
GHSA-g4x4-8j33-p4h3
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Remote unauthenticated message flooding with no user interaction against an exposed WebSocket endpoint (AV:N/AC:L/PR:N/UI:N); impact is JVM crash only, so A:H with C:N/I:N and no scope change.
Primary rating from Vendor (redhat).
CVSS VectorVendor: redhat
Lifecycle Timeline
3DescriptionCVE.org
A flaw was found in quarkus-websockets-next. This vulnerability allows a remote attacker to cause a Denial of Service (DoS) by streaming messages over a single connection faster than the application can process them. Due to unbounded message buffering and a lack of read backpressure, this rapidly exhausts heap space, leading to a java.lang.OutOfMemoryError that crashes the Java Virtual Machine (JVM).
AnalysisAI
Denial of service in the Red Hat Quarkus WebSockets Next extension (quarkus-websockets-next), as shipped in Red Hat Build of Quarkus and Red Hat Enterprise Linux AI (RHEL AI) 3, allows a remote, unauthenticated attacker to crash the Java Virtual Machine by streaming WebSocket messages over a single connection faster than the application can consume them. Unbounded message buffering combined with a lack of read backpressure exhausts heap memory, producing a java.lang.OutOfMemoryError that terminates the JVM and takes the hosting service offline; the assessed CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H, 7.5) confirms availability-only impact with no confidentiality or integrity loss and requires no authentication, user interaction, or special configuration beyond an attacker-reachable WebSocket endpoint. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The target application must be built on quarkus-websockets-next and expose at least one WebSocket endpoint that accepts inbound messages from network clients. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) is availability-only and internally consistent with the described flaw: a remote, unauthenticated attacker over the network with low complexity can stream WebSocket messages faster than the application drains them, and unbounded buffering plus missing read backpressure drives the JVM to OutOfMemoryError and crash. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | No fixed version is specified in the provided intelligence, so the first step is to monitor the Red Hat advisory at https://access.redhat.com/security/cve/CVE-2026-87742 and Bugzilla 2530522 for the release that introduces bounded inbound buffering and read backpressure, then upgrade the Red Hat Build of Quarkus and RHEL AI 3 packages carrying quarkus-websockets-next once a patched build is named. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory all services running Red Hat Build of Quarkus or RHEL AI 3 that expose WebSocket endpoints via the quarkus-websockets-next extension and confirm which are reachable from untrusted networks; apply network-level restrictions so only known client addresses can open WebSocket connections, and where that is not feasible, place connection-rate and concurrent-connection limits at the load balancer or reverse proxy in front of the service. …
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