Cyber Resilience

CVE-2026-16365

Mozilla Firefox ≤ 153.0.0

Published
21 July 2026
Modified
24 July 2026
Patch / advisory
CVSS Score v3.1 8.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.0027 19th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-16365 is a high-severity Improper Privilege Management (CWE-269) vulnerability in Mozilla Firefox. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 19th 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 AC-3 (Access Enforcement) and AC-6 (Least Privilege) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Privilege escalation in the DOM: Workers component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
Why these techniques?

Privilege escalation vulnerability in browser DOM Workers component directly enables T1068 Exploitation for Privilege Escalation.

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

CVEs Like This One

CVE-2026-8972Same product: Mozilla Firefox
CVE-2026-16401Same product: Mozilla Firefox
CVE-2026-2780Same product: Mozilla Firefox
CVE-2026-16396Same product: Mozilla Firefox
CVE-2026-16372Same product: Mozilla Firefox
CVE-2026-16379Same product: Mozilla Firefox
CVE-2026-2782Same product: Mozilla Firefox
CVE-2026-16371Same product: Mozilla Firefox
CVE-2026-12313Same product: Mozilla Firefox
CVE-2026-2777Same product: Mozilla Firefox

Affected Assets

mozilla
firefox
≤ 153.0.0
mozilla
thunderbird
≤ 153.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • AC-3 Access Enforcement
  • AC-6 Least Privilege
  • SC-39 Process Isolation
Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 13 hardening rules · 9 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V10.3.5

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly enforces access control policies to block unauthorized privilege escalation in DOM Workers.

prevent

Enforces least privilege for worker processes, directly mitigating CWE-269 improper privilege management.

prevent

Provides process isolation boundaries that limit the blast radius of a DOM Workers privilege escalation.

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.AA-05 mostly match
prevents

PR.AA-05 enforces least privilege/SoD and periodic reviews that directly remove most privilege-assignment defects, yet CWE-269 also covers escalation paths and role design outside a single access-management control.

PR.PS-01 mostly match
prevents

Hardened baselines and deviation monitoring directly eliminate most configuration-induced access-control defects, yet CWE-284 also encompasses code-level and design flaws outside the scope of configuration management alone.

PR.PS-06 mostly match
prevents

Secure SDLC practices catch most access-control defects during design/coding/testing (mostly), yet leave residual risk from runtime configuration, architecture, and operational controls (partial).

PR.AA-01 partial match
prevents

PR.AA-01 supplies credential/identity lifecycle support that can reduce some privilege-assignment errors but does not itself assign, modify, or check privileges, leaving most of CWE-269's risk unaddressed.

PR.AA-03 partial match
prevents

Authentication directly blocks unauthenticated actors (partial prevention of CWE-284) but leaves authorization logic, policy enforcement, and role checks untouched, so the control neither eliminates nor fully mitigates the broader weakness.

PR.DS-01 partial match
prevents

PR.DS-01 encryption mitigates impact of failed access checks on stored data but neither implements nor constrains access-control logic itself.

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.

prevents

Defining and enforcing explicit access rights and restrictions for each entity directly stops the assignment of permissions that exceed what is required, eliminating the root condition that allows improper access control.

prevents

Formal authorization, role-based provisioning, and timely revocation of access rights directly stop the creation of accounts or permissions that exceed what the business actually needs.

prevents

By enforcing explicit rules on which identities or groups may perform read, write, delete or execute operations and by denying anonymous access to sensitive data, the control directly stops the creation of overly permissive or missing access-control checks.

prevents

Requiring one-to-one mapping of identities to entities and timely removal of unused identities directly stops attackers from leveraging stale or shared accounts to bypass access restrictions.

prevents

By explicitly transferring security roles and responsibilities when personnel change jobs or leave, the control reduces the chance that former employees retain access rights they no longer need, thereby limiting improper access control.

prevents

Physical entry controls enforce explicit authorization and authentication at every access point, directly stopping unauthorized actors from reaching information-processing assets.

References