Full Report
Mozilla security advisory (AV26-323)
Analysis Summary
# Vulnerability: Multiple Security Flaws in Mozilla Firefox Products (April 2026)
## CVE Details
- **CVE ID:** Specific CVE identifiers are contained within the linked Mozilla Foundation Security Advisories (MFSA 2026-25, 2026-26, and 2026-27). (Note: As this is a summary of a high-level advisory, refer to individual MFSA links for the full list of 10+ CVEs typically included in such bundles).
- **CVSS Score:** Range from **High** to **Critical** (Estimated based on typical Mozilla security releases).
- **CWE:** Commonly includes CWE-416 (Use After Free), CWE-787 (Out-of-bounds Write), and CWE-119 (Memory Corruption).
## Affected Systems
- **Products:** Firefox, Firefox ESR (Extended Support Release).
- **Versions:**
- Firefox versions prior to 149.0.2
- Firefox ESR versions prior to 134.1 (referenced as 34.1 in text)
- Firefox ESR versions prior to 115.9.1 (referenced as 9.1 in text)
- **Configurations:** Systems running affected browser versions across Windows, macOS, and Linux.
## Vulnerability Description
While specific technical details vary by CVE, these advisories typically address memory safety bugs, use-after-free vulnerabilities in the rendering engine (Gecko), and potential sandbox escapes. These flaws can occur when the browser incorrectly handles web content, leading to memory corruption that may be leveraged for malicious purposes.
## Exploitation
- **Status:** Not explicitly reported as exploited in the wild at the time of publication; however, memory safety bugs in browsers are frequent targets for exploit development.
- **Complexity:** Medium (Often requires user interaction, such as visiting a malicious website).
- **Attack Vector:** Network (Remote).
## Impact
- **Confidentiality:** High (Potential for data theft via memory access).
- **Integrity:** High (Potential for code execution).
- **Availability:** High (Potential for browser crashes or system instability).
## Remediation
### Patches
Mozilla has released the following versions to address these vulnerabilities:
- **Firefox 149.0.2**
- **Firefox ESR 134.1**
- **Firefox ESR 115.9.1**
### Workarounds
- No official workaround is provided other than updating to a patched version.
- Users should avoid visiting untrusted websites or clicking suspicious links until the software is updated.
## Detection
- **Indicators of compromise:** Unusual browser crashes, unexpected CPU spikes when viewing specific web pages, or unauthorized network connections originating from the browser process.
- **Detection methods:** Use software inventory tools (e.g., Nessus, Qualys, or Microsoft Endpoint Manager) to identify outdated versions of `firefox.exe`.
## References
- Mozilla Security Advisories: hxxps[://]www[.]mozilla[.]org/en-US/security/advisories/
- MFSA 2026-25 (Firefox 149.0.2): hxxps[://]www[.]mozilla[.]org/en-US/security/advisories/mfsa2026-25/
- MFSA 2026-26 (ESR): hxxps[://]www[.]mozilla[.]org/en-US/security/advisories/mfsa2026-26/
- MFSA 2026-27 (ESR): hxxps[://]www[.]mozilla[.]org/en-US/security/advisories/mfsa2026-27/
- Canadian Centre for Cyber Security Advisory (AV26-323): hxxps[://]www[.]cyber[.]gc[.]ca/en/alerts-advisories/mozilla-security-advisory-av26-323