Mozilla Firefox CVE-2026-100826

Exploitation requires a victim using Firefox before 157 / ESR 153.4 to visit or render attacker-controlled web content that exercises the Storage: StorageManager component (UI:R - user interaction is required; the attack is not passive or self-propagating). No authentication and no special privileges are needed (PR:N), and no non-default configuration is indicated - standard browsing of a malicious page is sufficient. The primary limiting factors are the required user interaction, the availability-only outcome (crash/hang, no data compromise), and that patched versions (Firefox 157, ESR 153.4) fully remediate.

This is a genuine but moderate-severity issue best characterized as high-availability-impact but low-real-world-urgency. The CVSS 6.5 vector (AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H) is availability-only - no confidentiality or integrity impact - consistent with CWE-770 (uncontrolled resource allocation) causing a denial-of-service, not memory corruption or code execution. All exploitation signals point to low priority: SSVC scores Exploitation:none, Automatable:no, Technical Impact:partial; there is no EPSS score, no CISA KEV listing, and no public POC. The disclosure is a Mozilla self-report tied to a routine security-release batch (MFSA2026-97/100), which is the normal pipeline for coordinated fixes rather than an indicator of in-the-wild abuse. The AV:N with UI:R combination means an attacker cannot exploit passively - a victim must be lured to a crafted page - which further limits practical impact. Net: a real, patchable browser DoS but not an emergency; prioritize via normal browser-update cadence. Note the description says 'Denial-of-service' generically and does not detail the resource that is exhausted (memory, storage quota, handles) - verify specifics against the Mozilla advisory/bugzilla if a precise trigger is needed.

An attacker hosts or injects a malicious web page that drives the Storage: StorageManager component to allocate resources without bound. When a Firefox user visits the page (satisfying UI:R), the browser tab or process exhausts memory/resources and crashes or hangs, denying service. No public exploit code is available and there is no evidence of active exploitation.