CVE-2026-124683
Inefficient tokenization in Eclipse Langium allows DoS via crafted indented documents.
Is CVE-2026-124683 being exploited?
Not confirmed. CVE-2026-124683 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked.
How severe is CVE-2026-124683?
CVE-2026-124683 is rated High with a CVSS score of 8.7. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-124683?
Yes. A fix has been recorded for CVE-2026-124683. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-124683 affect?
CVE-2026-124683 affects Eclipse Langium 3.2.0-4.4.0, IndentationAwareTokenBuilder, IndentationAwareLexer, Node.js processes using Langium tokenization. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-124683?
Disable IndentationAware components or block untrusted documents; apply vendor patch when released.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
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.
Patch when possible
- affected>= 3.2.0 and <= 4.4.0
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
cisa ssvc
- exploitation
- none
- automatable
- yes
- technical impact
- partial
Assessed by CISA 9 Nov 2026 (SSVC 2.0.3).
timeline
- 9 Nov 2026Published
- 9 Nov 2026CISA SSVC assessment: exploitation none · same day later
- 9 Nov 2026CVE record last updated · same day later
- 10 Nov 2026Analysed by vulneraibility.com · 1 day later
also known as
- Linkgitlab.eclipse.org /security/vulnerability-reports/-/work_items/1069
- Linkgithub.com /eclipse-langium/langium/security/advisories/GHSA-297v-g8mm-qj4h
- Linkgitlab.eclipse.org /security/cve-assignment/-/work_items/553
sources
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
- OSV: advisory aliases and downstream package versions
- Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.