Full Report
Mozilla security advisory (AV26-726)
Analysis Summary
# Vulnerability: Multiple Vulnerabilities in Mozilla Firefox and Firefox ESR (July 2026)
## CVE Details
- **CVE ID:** Multiple (referencing MFSA 2026-68, 2026-69, 2026-70)
- **CVSS Score:** Estimated 8.8 - 9.8 (Critical)
- **CWE:** Typically includes Memory Safety flaws (CWE-119), Use-After-Free (CWE-416), or Type Confusion (CWE-843) based on Critical rating.
## Affected Systems
- **Products:**
- Mozilla Firefox
- Mozilla Firefox ESR (Extended Support Release)
- **Versions:**
- Firefox versions prior to 153
- Firefox ESR 140 versions prior to 140.13
- Firefox ESR 115 versions prior to 115.38
- **Configurations:** Default browser configurations; typically impacts users visiting malicious or compromised websites.
## Vulnerability Description
While the specific technical breakdown of each individual CVE is detailed in the linked advisories, the "Critical" designation for Mozilla products generally indicates memory corruption flaws. These vulnerabilities typically allow for arbitrary code execution within the browser's process. The flaws likely involve the rendering engine (Gecko) or JavaScript engine (SpiderMonkey), where insufficient bounds checking or incorrect object lifecycle management occurs.
## Exploitation
- **Status:** Not explicitly stated as exploited in the wild in the summary, but rated Critical, which often implies high exploitability or discovery of PoC during internal audits.
- **Complexity:** Medium (Typically requires tricking a user into navigating to a malicious URL).
- **Attack Vector:** Network (Remote)
## Impact
- **Confidentiality:** High
- **Integrity:** High
- **Availability:** High
*Note: Successful exploitation can lead to a full sandbox escape or arbitrary code execution.*
## Remediation
### Patches
Update to the following versions or higher:
- **Firefox:** 153
- **Firefox ESR:** 140.13
- **Firefox ESR:** 115.38
### Workarounds
- There are no supported workarounds that fully address these vulnerabilities.
- Users should avoid clicking on suspicious links or visiting untrusted websites until the update is applied.
## Detection
- **Indicators of Compromise:** Browser crashes when rendering specific web content; unauthorized process spawning from Firefox (e.g., cmd.exe or sh).
- **Detection methods and tools:**
- Vulnerability scanners (Nessus, Qualys) checking for installed browser versions.
- Endpoint Detection and Response (EDR) monitoring for suspicious child processes of `firefox.exe`.
## References
- Mozilla Foundation Security Advisory 2026-70: hxxps[://]www[.]mozilla[.]org/en-US/security/advisories/mfsa2026-70/
- Mozilla Foundation Security Advisory 2026-69: hxxps[://]www[.]mozilla[.]org/en-US/security/advisories/mfsa2026-69/
- Mozilla Foundation Security Advisory 2026-68: hxxps[://]www[.]mozilla[.]org/en-US/security/advisories/mfsa2026-68/
- Cyber Centre Advisory (AV26-726): hxxps[://]www[.]cyber[.]gc[.]ca/en/alerts-advisories/mozilla-security-advisory-av26-726