Cyber Resilience

CVE-2026-16395

Memory Safety in Mozilla Firefox ≤ 153.0.0

Published
21 July 2026
Modified
22 July 2026
Patch / advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0034 26th percentile
Risk Priority 70 floored blend · peak EPSS

Summary

CVE-2026-16395 is a critical-severity Integer Overflow or Wraparound (CWE-190) vulnerability in Mozilla Firefox. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked at the 26th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SI-2 (Flaw Remediation) and RA-5 (Vulnerability Monitoring and Scanning) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

Integer overflow in the Audio/Video component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
Why these techniques?

Integer overflow in browser media component enables client-side code execution via malicious content (T1203).

Confidence: MEDIUM · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-5732Same product: Mozilla Firefox
CVE-2026-16408Same product: Mozilla Firefox
CVE-2026-4705Same product: Mozilla Firefox
CVE-2026-16411Same product: Mozilla Firefox
CVE-2025-11152Same product: Mozilla Firefox
CVE-2026-14241Same product: Mozilla Firefox
CVE-2026-6756Same product: Mozilla Firefox
CVE-2026-10701Same product: Mozilla Firefox
CVE-2026-16402Same product: Mozilla Firefox
CVE-2026-8949Same product: Mozilla Firefox

Affected Assets

mozilla
firefox
≤ 153.0.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SI-2 Flaw Remediation
  • SI-7 Software, Firmware, and Information Integrity
Detect
Catch it (NIST detect / respond)
  • SI-7 Software, Firmware, and Information Integrity
  • RA-5 Vulnerability Monitoring and Scanning
Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V5.2.6

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly requires timely application of the vendor patch that eliminates the integer overflow in the Audio/Video component.

preventdetect

Verifies integrity of browser binaries and libraries, detecting unauthorized changes that could trigger or exploit the overflow.

detect

Scans for the presence of vulnerable Firefox/Thunderbird versions before exploitation of the CWE-190 flaw can occur.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require use of safe arithmetic, bounds checks, and testing that prevent integer overflows.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

detects

Security testing in development can detect integer overflows before release.

prevents

Secure SDLC mandates input validation and arithmetic checks that prevent integer overflows.

degrades

Application security requirements include bounds checking and safe arithmetic to avoid overflow conditions.

degrades

Secure architecture principles require defensive coding patterns that mitigate integer wraparound risks.

prevents

Secure coding standards explicitly forbid unsafe integer operations and mandate overflow-safe constructs.

References