CVSS 4.0
8.7 highCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NCVE-2026-124683 eclipse foundation eclipse langium: Inefficient Algorithmic Complexity
High (8.7) in eclipse foundation eclipse langium. EPSS 0.5% estimated probability of exploitation activity in the next 30 days.
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.
Severity
- EPSS
- 0.5% estimated probability of exploitation activity in the next 30 days; 43rd percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: none · Automatable: yes · Technical impact: partial, assessed 2026-11-09. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- CWE
- CWE-407 Inefficient Algorithmic Complexity
- Published
- Modified
- NVD analysis
- Deferred: the NVD does not plan to analyze it
- Record from
- the NVD, synced
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Affected
- eclipse foundation:eclipse langium
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| Eclipse Foundation Eclipse Langium | from 3.2.0 through 4.4.0 |
History
- The NVD deferred its analysis
Changes since this site first stored the record. The same for every record: /api/public/changes.