---
id: "CVE-2026-117915"
kind: "vulnerability"
aliases: ["CVE-2026-117915"]
title: "Firefox: layout engine boundary bug fixed in Firefox 159"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["desktop-browsers", "firefox", "runtime"]
not_affected_if: ["fixed-version"]
published_at: "2026-10-27T14:16:46+00:00"
first_seen_at: "2026-10-27T14:32:22+00:00"
updated_at: "2026-10-27T14:37:23+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-117915", "first_seen_at": "2026-10-27T14:32:22+00:00"}]
---

# Firefox: layout engine boundary bug fixed in Firefox 159

Firefox's Block and Inline layout component mishandles boundary conditions, a memory-safety style flaw the sources do not detail. The fix shipped in Firefox 159, Firefox ESR 115.44 and Firefox ESR 153.6, and the sources do not say what an attacker gets from it.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Run `firefox --version` or check About Firefox and compare against `159`, `115.44` or `153.6` for ESR
- unknown for anything beyond the version

## Fix

- Update Firefox to `159` or later
- Update Firefox ESR to `115.44` or `153.6`

## Timeline

- 2026-10-27T14:32:22+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-117915

## From the sources

Incorrect boundary conditions in the Layout: Block and Inline component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, and Firefox ESR 153.6.

---

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