Cyber Resilience

CVE-2026-16386

Mozilla Firefox ≤ 153.0.0

Published
21 July 2026
Modified
27 July 2026
Patch / advisory
CVSS Score v3.1 7.5
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:N/A:N
EPSS Score 0.0031 24th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-16386 is a high-severity Use of Uninitialized Resource (CWE-908) vulnerability in Mozilla Firefox. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Data from Local System (T1005); ranked at the 24th 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-16 (Memory Protection) and SI-2 (Flaw Remediation) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

Information disclosure due to uninitialized memory in the Graphics: WebGPU component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
Why these techniques?

Uninitialized memory information disclosure in browser graphics component directly enables reading sensitive data from local process memory (T1005).

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

CVEs Like This One

CVE-2026-16385Same product: Mozilla Firefox
CVE-2026-16384Same product: Mozilla Firefox
CVE-2026-6772Same product: Mozilla Firefox
CVE-2026-6770Same product: Mozilla Firefox
CVE-2026-6766Same product: Mozilla Firefox
CVE-2025-1942Same product: Mozilla Firefox
CVE-2026-6767Same product: Mozilla Firefox
CVE-2026-16391Same product: Mozilla Firefox
CVE-2026-4716Same product: Mozilla Firefox
CVE-2026-2783Same product: Mozilla Firefox

Affected Assets

mozilla
firefox
≤ 153.0.0
mozilla
thunderbird
≤ 153.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly implements memory protection safeguards that prevent disclosure of uninitialized memory contents in components such as WebGPU.

prevent

Enforces process isolation so that uninitialized memory in the graphics/WebGPU process cannot be read by other browser processes or content.

prevent

Requires timely remediation of coding flaws such as CWE-908 use of uninitialized resources, matching the exact fix shipped in Firefox/Thunderbird 153.

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 activities such as static analysis and code review directly prevent use of uninitialized resources while also addressing many other weaknesses.

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 and acceptance can detect uninitialized resource usage through dynamic analysis and fuzzing.

prevents

Secure development life cycle mandates initialization checks and static analysis that can catch uninitialized resource use.

prevents

Application security requirements can specify mandatory initialization of variables and resources before use.

prevents

Secure system architecture and engineering principles include defensive coding practices that prevent use of uninitialized memory or objects.

prevents

Secure coding standards directly require explicit initialization of all variables and resources, substantially mitigating CWE-908.

References