CVE-2026-4708
Published: 24 March 2026
Summary
CVE-2026-4708 is a high-severity Improper Check for Unusual or Exceptional Conditions (CWE-754) vulnerability in Mozilla Firefox. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 34.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-2 (Flaw Remediation) and RA-5 (Vulnerability Monitoring and Scanning).
Deeper analysis
CVE-2026-4708 is a vulnerability involving incorrect boundary conditions in the Graphics component of Mozilla products. It affects Firefox, Firefox ESR, Thunderbird, and Thunderbird ESR, with fixes applied in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9. The issue is classified under CWE-754 (Improper Check for Unusual or Exceptional Conditions) and received a CVSS v3.1 base score of 7.5.
An unauthenticated attacker can exploit this vulnerability remotely over the network with low complexity and no user interaction required. Successful exploitation results in high-impact denial of service, such as application crashes, without affecting confidentiality or integrity.
Mozilla's security advisories (MFSA 2026-20, 2026-22, 2026-23, and 2026-24) and the associated Bugzilla entry (bug 2015268) detail the patches released in the specified versions, recommending users upgrade immediately to mitigate the risk.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-14831
Vulnerability details
Incorrect boundary conditions in the Graphics component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Remote unauthenticated exploitation of graphics boundary condition flaw directly enables application crashes for denial of service, mapping to T1499.004 Application or System Exploitation.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly mandates timely remediation of the graphics component boundary condition flaw in Mozilla products via patching to fixed versions like Firefox 149.
Enables identification of systems vulnerable to CVE-2026-4708 through ongoing vulnerability scanning of Firefox and Thunderbird installations.
Addresses CWE-754 improper checks for exceptional conditions by requiring the system to handle boundary errors in the Graphics component without causing DoS crashes.
Hardening callouts derived
Configuration rules from DISA STIG baselines that reduce the attack surface for weaknesses of the type cited by this CVE. Derived transitively via CVE→CWE→STIG over `controls_xwalks` (authoritative rows only).
Oracle Linux 8 (3 rules)
- V-248574 YUM must be configured to prevent the installation of patches, service packs, device drivers, or OL 8 system components that have not been digitally signed using a certificate that is recognized and approved by the organization. via CWE-754
- V-248573 The OL 8 file integrity tool must notify the system administrator (SA) when changes to the baseline configuration or anomalies in the operation of any security functions are discovered within an organizationally defined frequency. via CWE-754
- V-248575 OL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. via CWE-754
Oracle Linux 9 (1 rule)
- V-271452 OL 9 must use a Linux Security Module configured to enforce limits on system services. via CWE-754