CVE-2026-108748: Quarkus LangChain4j 1.9.0 through 1.14.1 Memory Exhaustion via /_chat/routes WebSocket

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-11 · updated 2026-10-16
Weakness: CWE-401

Description

Quarkus LangChain4j 1.9.0 through 1.14.1 contains a missing release of memory vulnerability in the chat-scopes WebSocket /_chat/routes endpoint that allows unauthenticated remote clients to exhaust server memory. Attackers can send repeated CONNECT frames reusing one chatId, leaving orphaned scopes in activeScopes until the JVM exits and degrading availability.

Affected products

quarkiverse quarkus-langchain4j: from 1.9.0 through 1.14.1

References

https://github.com/quarkiverse/quarkus-langchain4j
https://github.com/quarkiverse/quarkus-langchain4j/blob/658ac8268e1a453a6a2066952d9495fb925479e3/chat-scopes/core/runtime/src/main/java/io/quarkiverse/langchain4j/chatscopes/internal/ChatScopeManagedContext.java#L297-L311
https://github.com/quarkiverse/quarkus-langchain4j/blob/658ac8268e1a453a6a2066952d9495fb925479e3/chat-scopes/websocket/runtime/src/main/java/io/quarkiverse/langchain4j/chatscopes/websocket/internal/ChatRouteEndpoint.java#L122-L160
https://hackmd.io/@haind/quarkus-langchain4j-chatscope-orphan-leak
https://www.vulncheck.com/advisories/quarkus-langchain4j-1.9.0-through-1.14.1-memory-exhaustion-via-chat-routes-websocket
https://hackmd.io/@haind/quarkus-langchain4j-chatscope-orphan-leak

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