Cyber Resilience

CVE-2026-12298

Memory Safety in Mozilla Firefox ≤ 152.0

Published
16 June 2026
Modified
15 July 2026
Patch / advisory
CVSS Score v3.1 5.4
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
EPSS Score 0.0031 23th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-12298 is a medium-severity Out-of-bounds Read (CWE-125) vulnerability in Mozilla Firefox. Its CVSS base score is 5.4 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Drive-by Compromise (T1189); ranked at the 23th 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 SC-39 (Process Isolation) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

Memory safety bug fixed in Firefox 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1189 Drive-by Compromise Initial Access
Adversaries may gain access to a system through a user visiting a website over the normal course of browsing.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
Why these techniques?

Memory corruption weaknesses (CWE-416/787/125) in browser directly enable drive-by client-side exploitation for code execution.

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

CVEs Like This One

CVE-2025-1016Same product: Mozilla Firefox
CVE-2025-0247Same product: Mozilla Firefox
CVE-2025-1020Same product: Mozilla Firefox
CVE-2025-1017Same product: Mozilla Firefox
CVE-2025-4918Same product: Mozilla Firefox
CVE-2025-4919Same product: Mozilla Firefox
CVE-2024-10467Same product: Mozilla Firefox
CVE-2025-0242Same product: Mozilla Firefox
CVE-2024-6615Same product: Mozilla Firefox
CVE-2025-5269Same product: Mozilla Firefox

Affected Assets

mozilla
firefox
≤ 152.0 · 140.0 — 140.12.0
mozilla
thunderbird
≤ 152.0.0 · 140.0 — 140.12.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
Detect
Catch it (NIST detect / respond)
  • SI-7 Software, Firmware, and Information Integrity
Harden
Shrink the surface (DISA STIG)
  • 3 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V1.4.3
  • V1.5.2
  • V3.2.3
  • V15.3.5

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly requires timely application of vendor patches that remediate the memory-safety flaws (CWE-416/787/125/843) in Firefox/Thunderbird.

detect

Requires integrity verification of browser binaries and libraries, enabling detection of unauthorized modification that could exploit or mask the memory corruption.

prevent

Mandates process isolation boundaries that limit the blast radius and privilege escalation possible from a successful use-after-free or out-of-bounds write inside the browser process.

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-development practices such as bounds checking and memory-safe languages directly prevent out-of-bounds reads.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover instances of out-of-bounds reads after code is deployed.

PR.PS-02 partial match
prevents

Routine patching replaces vulnerable code containing out-of-bounds read flaws.

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 includes fuzzing and static analysis that detect out-of-bounds read defects before release.

A.8.15 Logging partial match
detects

Logging can record evidence of an out-of-bounds read but does not prevent the weakness itself.

prevents

Secure development life cycle mandates input validation and bounds checking that directly prevent out-of-bounds reads.

prevents

Application security requirements include explicit bounds and memory-safety specifications that mitigate buffer over-reads.

prevents

Secure system architecture and engineering principles require memory-safe design patterns and runtime protections against out-of-bounds access.

prevents

Secure coding standards explicitly forbid unsafe pointer arithmetic and mandate bounds-checked reads, eliminating CWE-125.

References