HIGH 8.7 NVD
CVE-2026-124683
Eclipse Langium versions 3.2.0 through 4.4.0 contain an inefficient algorithmic complexity issue (CWE-407) in the opt-in IndentationAwareTokenBuilder and Indent
Eclipse Langium versions 3.2.0 through 4.4.0 contain an inefficient algorithmic complexity issue (CWE-407) in the opt-in IndentationAwareTokenBuilder and IndentationAwareLexer. When producing DEDENT tokens, the token builder recomputes line numbers by re-scanning the entire preceding document text. A document whose indentation changes on most lines then takes quadratic time to tokenize. Because tokenization is synchronous, a crafted document of a few hundred kilobytes can block the Node.js event loop for tens of seconds. That causes a DoS for every user served by the same process. Languages built with the DefaultLexer and DefaultTokenBuilder are unaffected.
References
- https://github.com/eclipse-langium/langium/security/advisories/GHSA-297v-g8mm-qj4h
- https://gitlab.eclipse.org/security/cve-assignment/-/work_items/553
- https://gitlab.eclipse.org/security/vulnerability-reports/-/work_items/1069
This high severity vulnerability with a CVSS score of 8.7 was published on 2026-11-09 via NVD.
vulnfeed aggregates 17092 vulnerabilities from NVD, CISA KEV,
Ubuntu, Debian, Red Hat, Kubernetes, Exploit-DB, OSS-Security, GitHub and OpenStack — updated every 4 hours.