CVE-2026-15718: Mozilla Firefox Privilege Escalation Flaw

CVE-2026-15718 Overview

CVE-2026-15718 is an information disclosure vulnerability affecting Mozilla Firefox before version 152.0.6. The flaw is categorized under [CWE-763] (Release of Invalid Pointer or Reference) and is exploitable over the network with user interaction required. Public exploit code exists for this issue, though Mozilla reports no observed exploitation in the wild. Mozilla addressed the vulnerability in Firefox 152.0.6 as part of security advisory MFSA-2026-67.

Critical Impact
An attacker can leverage a crafted web page to trigger the vulnerability and obtain limited confidential information from the browser process. Exploitation requires the victim to visit or interact with attacker-controlled content.

Affected Products

Mozilla Firefox versions prior to 152.0.6

Discovery Timeline

2026-07-14 - CVE-2026-15718 published to NVD
2026-07-14 - Mozilla releases security patch in Firefox 152.0.6 via Mozilla Security Advisory MFSA-2026-67
2026-07-14 - Last updated in NVD database

Technical Details for CVE-2026-15718

Vulnerability Analysis

CVE-2026-15718 is an information disclosure issue in Mozilla Firefox tied to improper handling of an invalid pointer or reference [CWE-763]. The condition allows a remote attacker who serves malicious web content to read limited data from the browser process. The vulnerability affects confidentiality only; integrity and availability are not directly impacted. Because public exploit code is available, defenders should treat unpatched Firefox installations as an active exposure. See Mozilla Bug Report #2045443 for the underlying technical discussion.

Root Cause

The root cause maps to [CWE-763], in which code releases or dereferences an invalid pointer or reference. When Firefox processes attacker-controlled web content, this incorrect memory reference leads to disclosure of small amounts of process memory to the calling context. Mozilla's fix in Firefox 152.0.6 corrects the pointer handling logic in the affected component.

Attack Vector

The attack vector is network-based and requires user interaction. A victim must load a malicious page or interact with attacker-controlled content in a vulnerable Firefox build. No authentication or elevated privileges are required to trigger the flaw. Successful exploitation returns partial memory contents to the attacker's JavaScript or web context, which can then be exfiltrated.

No verified proof-of-concept code is published in the referenced advisory. Refer to Mozilla Security Advisory MFSA-2026-67 for vendor technical details.

Detection Methods for CVE-2026-15718

Indicators of Compromise

Firefox client telemetry showing installed versions earlier than 152.0.6 in the enterprise fleet.
Browser process crashes or anomalous memory-access errors correlated with visits to untrusted domains.
Outbound web requests carrying unusually structured payloads immediately after page navigation events.

Detection Strategies

Inventory endpoints and enumerate Firefox versions to identify hosts running builds prior to 152.0.6.
Monitor endpoint logs for Firefox child process exceptions and abnormal renderer terminations.
Correlate DNS and HTTP telemetry with browsing to unclassified or newly registered domains that could host exploit pages.

Monitoring Recommendations

Track Firefox update compliance through configuration management tooling and enforce automatic updates.
Ingest browser and endpoint logs into a centralized data lake or SIEM to enable version-based hunting queries.
Alert on any Firefox binary running on unsupported or unpatched versions once patch rollout is complete.

How to Mitigate CVE-2026-15718

Immediate Actions Required

Upgrade all Mozilla Firefox installations to version 152.0.6 or later without delay.
Push the update through enterprise deployment tools to prevent user-driven update delays.
Restrict browsing to trusted sites on hosts that cannot be patched immediately.

Patch Information

Mozilla released the fix in Firefox 152.0.6. Administrators should consult Mozilla Security Advisory MFSA-2026-67 for the authoritative patch reference and Mozilla Bug Report #2045443 for the tracked defect. Enterprises using Firefox ESR should confirm equivalent fixes in their supported channel.

Workarounds

Where patching is not immediate, disable JavaScript on untrusted sites via browser policy or an extension such as NoScript.
Use enterprise policy files (policies.json) to enforce block-lists for high-risk domains until updates complete.
Consider temporary use of an alternative supported browser on hosts pending remediation.

bash

# Verify installed Firefox version on Linux/macOS
firefox --version

# Windows: query installed version via registry
reg query "HKLM\SOFTWARE\Mozilla\Mozilla Firefox" /v CurrentVersion

# Enterprise policy snippet to force automatic updates (policies.json)
# {
#   "policies": {
#     "DisableAppUpdate": false,
#     "AppAutoUpdate": true
#   }
# }