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VULNERABILITIES

CVE-2026-124683 Details

Description

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.

Metrics

CVSS 3.x Severity and Vector Strings:

No CVSS 3.x data is available for this CVE.

References to Advisories, Solutions, and Tools

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URLSource(s)Tag(s)
https://github.com/eclipse-langium/langium/security/advisories/GHSA-297v-g8mm-qj4h [email protected]
https://gitlab.eclipse.org/security/cve-assignment/-/work_items/553 [email protected]
https://gitlab.eclipse.org/security/vulnerability-reports/-/work_items/1069 [email protected]

Weakness Enumeration

CWE-IDCWE NameSource
CWE-407Inefficient Algorithmic Complexity[email protected]

Affected Products

No affected product data is available for this CVE.

Change History

2 change records found show changes

QUICK INFO

CVE Dictionary Entry:
CVE-2026-124683
NVD Published Date:
Nov 9, 2026
NVD Last Modified:
Nov 9, 2026
Source:
[email protected]
CVE-2026-124683 Details - Not Deferred