# CVE-2026-124683

Inefficient tokenization in Eclipse Langium allows DoS via crafted indented documents.

- Page: https://www.vulneraibility.com/cve/CVE-2026-124683
- CVSS: 8.7
- Known exploited: not in CISA KEV as of our last sync
- CISA SSVC: exploitation none, automatable yes, technical impact partial (assessed 2026-11-09)
- Weakness: CWE-407
- Also known as: GHSA-297v-g8mm-qj4h
- Published: 2026-11-09

## Affected versions

- Eclipse Foundation Eclipse Langium: affected >= 3.2.0 and <= 4.4.0

A version outside these ranges is not a statement that it is unaffected.

## Impact

Crafted documents trigger quadratic tokenization, blocking the Node.js event loop for tens of seconds and causing DoS for all users on the same process.

## Action

Patch when possible

## Recommendation

Disable IndentationAware components or block untrusted documents; apply vendor patch when released.

## References

- [other] https://gitlab.eclipse.org/security/vulnerability-reports/-/work_items/1069
- [other] https://github.com/eclipse-langium/langium/security/advisories/GHSA-297v-g8mm-qj4h
- [other] https://gitlab.eclipse.org/security/cve-assignment/-/work_items/553

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Summary, impact and action are written by the vulneraibility.com AI analysis pipeline from the CVE record, NVD, CISA and FIRST data; verify against the references.