Full Report
Mozilla security advisory (AV26-271)
Analysis Summary
# Vulnerability: Multiple Vulnerabilities in Mozilla Firefox Products (AV26-271)
## CVE Details
- **CVE ID:** Not explicitly listed in the summary document; multiple CVEs are addressed within the linked advisories (MFSA2026-20, MFSA2026-21, MFSA2026-22).
- **CVSS Score:** Range typically includes **High** to **Critical** for Mozilla security updates.
- **CWE:** Commonly includes memory safety bugs (CWE-119), Use-After-Free (CWE-416), and Type Confusion (CWE-843).
## Affected Systems
- **Products:**
- Mozilla Firefox
- Mozilla Firefox ESR (Extended Support Release)
- **Versions:**
- Firefox versions prior to 149
- Firefox ESR versions prior to 115.34
- Firefox ESR versions prior to 140.9
- **Configurations:** Standard installations of the browser on Windows, macOS, and Linux.
## Vulnerability Description
While the bulletin (AV26-271) serves as a high-level notification, Mozilla's documentation indicates these updates typically resolve memory safety vulnerabilities, some of which show evidence of memory corruption. These flaws could potentially be leveraged to bypass security sandboxes or execute arbitrary code in the context of the browser process.
## Exploitation
- **Status:** Not specified as exploited in the wild in this summary; refer to specific MFSA links for zero-day status.
- **Complexity:** Medium (Typically requires tricking a user into visiting a malicious website).
- **Attack Vector:** Network (Remote/Web-based).
## Impact
- **Confidentiality:** High (Potential for data theft).
- **Integrity:** High (Potential for unauthorized modification of data or system settings).
- **Availability:** High (Potential for application crashes or system instability).
## Remediation
### Patches
Apply the following updates provided by Mozilla:
- **Firefox:** Upgrade to version **149** or higher.
- **Firefox ESR:** Upgrade to version **115.34** or higher.
- **Firefox ESR:** Upgrade to version **140.9** or higher.
### Workarounds
- **No official workarounds provided.** Users are strongly advised to apply the security updates immediately as the primary defense.
- Maintain a "Least Privilege" user environment to limit the impact of a successful browser compromise.
## Detection
- **Indicators of Compromise:** Unusual browser crashes, unexpected outbound network traffic to known malicious IPs/domains, or unauthorized file system modifications.
- **Detection methods and tools:**
- Utilize Vulnerability Scanners (e.g., Nessus, Qualys) to identify outdated browser versions.
- Monitor endpoint logs for suspicious child processes spawning from `firefox.exe`.
## References
- **Vendor advisories:**
- hxxps[://]www[.]mozilla[.]org/en-US/security/advisories/mfsa2026-20/
- hxxps[://]www[.]mozilla[.]org/en-US/security/advisories/mfsa2026-21/
- hxxps[://]www[.]mozilla[.]org/en-US/security/advisories/mfsa2026-22/
- hxxps[://]www[.]mozilla[.]org/en-US/security/advisories/
- **Reporting Authority:**
- Canadian Centre for Cyber Security (Cyber Centre) Advisory AV26-271.