# CVE-2026-118492: CVE-2026-118492

Status: published. Published: 2026-11-09. Updated: 2026-11-09.

In Eclipse Langium versions 3.0.0 and later, the langium-sprotty package does not HTML-escape diagnostic messages before rendering them in the default hover popup provided by `addHoverPopupHandler`. If a Langium grammar allows cross-reference text to contain HTML markup (such as through a STRING terminal), an unresolved cross-reference produces a diagnostic message that includes the literal ref text. When a Sprotty diagram is opened for a malicious source file under these conditions, and a user hovers over the corresponding error marker, attacker-controlled JavaScript can execute in the browser or webview.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Eclipse Foundation / Eclipse Langium: ≥ 3.0.0; ≤ 4.4.0 (affected, semver). Source: CNA: eclipse

## Severity and prioritization

- CVSS 4.0: 2 (low); CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/AU:N/R:A/V:D; source: CNA: eclipse

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-79

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://gitlab.eclipse.org/security/vulnerability-reports/-/work_items/1018 (CNA: eclipse)

- https://github.com/eclipse-langium/langium/security/advisories/GHSA-7c4f-7qwx-hmcv (CNA: eclipse)

- https://gitlab.eclipse.org/security/cve-assignment/-/work_items/512 (CNA: eclipse)

## Provenance

- CNA: eclipse: https://www.cve.org/CVERecord?id=CVE-2026-118492; retrieved 2026-11-09; source updated 2026-11-09

Revision: e5fce75e43ada40e2218743349e8879521ed038aeb8791e012213fa2d1709e30

Canonical: https://y2.dev/cve/CVE-2026-118492

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