Full Report
Mozilla security advisory (AV26-976)
Analysis Summary
# Vulnerability: Multiple Vulnerabilities in Mozilla Firefox and Firefox ESR
## CVE Details
*Note: The source text references a collection of security advisories (MFSA 2026-97 through 2026-100). These typically include multiple CVEs ranging from High to Critical severity.*
- **CVE ID:** Multiple (refer to MFSA 2026-97, 2026-98, 2026-99, 2026-100)
- **CVSS Score:** Varies (Typically up to 9.8 for browser RCE vulnerabilities)
- **Severity:** High / Critical
- **CWE:** Varies (Typically includes Memory Safety, Use-after-free, and Type Confusion)
## Affected Systems
- **Products:** Mozilla Firefox, Mozilla Firefox ESR (Extended Support Release)
- **Versions:**
- Firefox versions prior to 157
- Firefox ESR versions prior to 153.4
- Firefox ESR versions prior to 140.17
- Firefox ESR versions prior to 115.42
- **Configurations:** Systems running the browser in standard desktop or enterprise environments.
## Vulnerability Description
Mozilla has addressed multiple security flaws across its browser suite. While specific technical breakdowns for each CVE are detailed in the individual MFSA links, these advisories generally cover:
1. **Memory Safety Bugs:** Vulnerabilities that allow for memory corruption, potentially leading to arbitrary code execution.
2. **Use-after-free:** Flaws in memory management where the program continues to use a pointer after it has been freed.
3. **Sandbox Escapes:** Flaws that could allow a malicious script to bypass the browser's security boundaries.
## Exploitation
- **Status:** Not explicitly stated as "exploited in the wild" in the summary; however, browser vulnerabilities of this nature are frequently targeted.
- **Complexity:** Medium to High (Usually requires crafting a malicious website).
- **Attack Vector:** Network (Remote/Web-based).
## Impact
- **Confidentiality:** High (Potential for data theft and session hijacking).
- **Integrity:** High (Potential for unauthorized system modification).
- **Availability:** High (Potential for application crashes or system instability).
## Remediation
### Patches
Users and administrators are urged to update to the following versions or later:
- **Firefox:** 157
- **Firefox ESR:** 153.4
- **Firefox ESR:** 140.17
- **Firefox ESR:** 115.42
### Workarounds
- **General Best Practices:** Avoid visiting untrusted websites or clicking suspicious links until the browser is updated.
- **Sandboxing:** Ensure OS-level sandboxing and security features (like DEP/ASLR) are enabled.
## Detection
- **Indicators of Compromise:** Unusual browser crashes, unauthorized outgoing network connections from the browser process, or unexpected file system modifications.
- **Detection methods:** Enterprise security suites (EDR/AV) should be monitored for exploitation attempts targeting browser memory.
## References
- Mozilla Foundation Security Advisories: hxxps[://]www[.]mozilla[.]org/en-US/security/advisories/
- MFSA 2026-97 (Firefox 157): hxxps[://]www[.]mozilla[.]org/en-US/security/advisories/mfsa2026-97/
- MFSA 2026-100 (Firefox ESR 153.4): hxxps[://]www[.]mozilla[.]org/en-US/security/advisories/mfsa2026-100/
- MFSA 2026-98 (Firefox ESR 115.42): hxxps[://]www[.]mozilla[.]org/en-US/security/advisories/mfsa2026-98/
- MFSA 2026-99 (Firefox ESR 140.17): hxxps[://]www[.]mozilla[.]org/en-US/security/advisories/mfsa2026-99/