# CVE-2026-117861: Sandbox escape in the DOM: Navigation component

Status: published. Published: 2026-10-27. Updated: 2026-11-04.

Sandbox escape in the DOM: Navigation component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Mozilla / Firefox: ≥ 153.6; ≤ 153.* (unaffected, rpm); ≥ 159; ≤ * (unaffected, rpm). Source: CNA: mozilla
- Mozilla / Thunderbird: ≥ 153.6; ≤ 153.* (unaffected, rpm); ≥ 159; ≤ * (unaffected, rpm). Source: CNA: mozilla

## Severity and prioritization

- CVSS 3.1: 9.6 (critical); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H; source: ADP: CISA-ADP

- CISA KEV: No listing in collected sources

- EPSS: 0.18% as of 2026-11-04; percentile 7.79%

- SSVC: exploitation none; automatable no; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-693

## Exploit evidence

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

## References

- https://bugzilla.mozilla.org/show_bug.cgi?id=2053240 (CNA: mozilla)

- https://www.mozilla.org/security/advisories/mfsa2026-118/ (CNA: mozilla)

- https://www.mozilla.org/security/advisories/mfsa2026-120/ (CNA: mozilla)

- https://www.mozilla.org/security/advisories/mfsa2026-121/ (CNA: mozilla)

- https://www.mozilla.org/security/advisories/mfsa2026-122/ (CNA: mozilla)

## Provenance

- CNA: mozilla: https://www.cve.org/CVERecord?id=CVE-2026-117861; retrieved 2026-11-04; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-117861; retrieved 2026-11-04; source updated Not reported

Revision: 4ab608ebd0563f51e20bd3f5eb64636cb135e222b851ec4f8640260769b7fc13

Canonical: https://y2.dev/cve/CVE-2026-117861

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