Cyber Resilience

CVE-2026-12294

Mozilla Firefox ≤ 115.37.0

Published
16 June 2026
Modified
15 July 2026
Patch / advisory
View advisory
CVSS Score v3.1 9.6
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
EPSS Score 0.0036 30th percentile
Risk Priority 67 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-12294 is a critical-severity Protection Mechanism Failure (CWE-693) vulnerability in Mozilla Firefox. Its CVSS base score is 9.6 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Network Sniffing (T1040); ranked at the 30th 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-4 (Information Flow Enforcement) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A06:2025 Insecure Design

EU & UK References

Vulnerability Data

Sandbox escape in the DOM: Workers component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.

CWE(s)
CWE-693CWE-266

Related Threats

MITRE ATT&CK Enterprise Techniques

T1040 Network Sniffing Credential Access
Adversaries may passively sniff network traffic to capture information about an environment, including authentication material passed over the network.
attack.mitre.org →
T1565.002 Transmitted Data Manipulation Impact
Adversaries may alter data en route to storage or other systems in order to manipulate external outcomes or hide activity, thus threatening the integrity of the data.
attack.mitre.org →
T1574.005 Executable Installer File Permissions Weakness Stealth
Adversaries may execute their own malicious payloads by hijacking the binaries used by an installer.
attack.mitre.org →
T1574.010 Services File Permissions Weakness Stealth
Adversaries may execute their own malicious payloads by hijacking the binaries used by services.
attack.mitre.org →
T1611 Escape to Host Privilege Escalation
Adversaries may break out of a container or virtualized environment to gain access to the underlying host.
attack.mitre.org →
T1078 Valid Accounts Stealth
Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-8969Same product: Mozilla Firefox
CVE-2026-16390Same product: Mozilla Firefox
CVE-2026-6774Same product: Mozilla Firefox
CVE-2026-74959Same product: Mozilla Firefox
CVE-2026-16377Same product: Mozilla Firefox
CVE-2026-74957Same product: Mozilla Firefox
CVE-2026-2761Same product: Mozilla Firefox
CVE-2026-8962Same product: Mozilla Firefox
CVE-2026-0877Same product: Mozilla Firefox
CVE-2026-6763Same product: Mozilla Firefox

Affected Assets

mozilla
firefox
≤ 115.37.0 · ≤ 152.0.0 · 128.0 — 140.12.0
mozilla
thunderbird
≤ 140.12.0 · ≤ 152.0.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 14 hardening rules · 9 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V6.3.3
  • V6.6.3
  • V10.2.2

Mitigating Controls (NIST 800-53 r5) AI

AC-3 Access Enforcement good match

AC-3 directly requires enforcement of access authorizations via the protection mechanism itself.

AC-4 Information Flow Enforcement good match

AC-4 mandates use of information flow enforcement mechanisms to control data movement.

SC-2 Separation of System and User Functionality good match

SC-2 requires separation of user and system functionality as a protection mechanism.

SC-28 Protection of Information at Rest good match

SC-28 requires protection mechanisms for information at rest.

SC-3 Security Function Isolation good match

SC-3 requires isolation of security functions from non-security functions.

SC-7 Boundary Protection good match

SC-7 requires boundary protection mechanisms to monitor and control external communications.

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-03 partial match
prevents

Enforcing authentication directly implements a core protection mechanism whose absence or misuse is the CWE.

PR.AA-05 partial match
prevents

Defining and enforcing access authorizations is a protection mechanism; proper use prevents the CWE.

PR.DS-01 partial match
prevents

Cryptographic and integrity controls are protection mechanisms whose correct deployment mitigates the CWE.

PR.DS-02 partial match
prevents

Encryption and integrity protections for transit are explicit protection mechanisms.

PR.IR-01 partial match
prevents

Logical network protections are protection mechanisms whose failure matches the CWE.

PR.PS-01 partial match
prevents

Hardened configuration baselines ensure protection mechanisms are correctly applied and maintained.

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.

A.5.15 Access control partial match
prevents

Access control policy directly prevents incorrect privilege assignment by defining who may receive which rights.

A.5.18 Access rights partial match
prevents

The access-rights control governs the entire lifecycle of privilege assignment, directly eliminating incorrect assignments.

A.5.3 Segregation of duties partial match
mitigates

Segregation of duties reduces blast radius of any single incorrect privilege but does not prevent the assignment itself.

A.5.36 Compliance with policies, rules and standards for information security partial match
finds

Systematic verification that security mechanisms operate according to defined standards reduces the likelihood that protection mechanisms are bypassed or disabled.

A.8.18 Use of privileged utility programs partial match
mitigates

Restricting privileged utility programs limits exposure from over-privileged accounts but does not address how privileges are assigned.

A.8.2 Privileged access rights partial match
prevents

Privileged-access-rights control explicitly requires least-privilege assignment and ongoing validation, directly mitigating CWE-266.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (higher-evidence rows only; rows rated `none` are excluded).

Oracle Linux 8 (3 rules)
  • V-248524 OL 8 must implement NIST FIPS-validated cryptography for the following: To provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-693
  • V-248525 All OL 8 local disk partitions must implement cryptographic mechanisms to prevent unauthorized disclosure or modification of all information that requires at-rest protection. prevents CWE-693
  • V-248551 A sticky bit must be set on all OL 8 public directories to prevent unauthorized and unintended information transferred via shared system resources. prevents CWE-266
Oracle Linux 9 (1 rule)
  • V-271779 OL 9 must be configured so that a sticky bit must be set on all public directories. prevents CWE-266
RHEL 8 (1 rule)
  • V-230243 A sticky bit must be set on all RHEL 8 public directories to prevent unauthorized and unintended information transferred via shared system resources. prevents CWE-266
RHEL 9 (1 rule)
  • V-257929 A sticky bit must be set on all RHEL 9 public directories. prevents CWE-266
Ubuntu 22.04 (2 rules)
  • V-260513 Ubuntu 22.04 LTS must set a sticky bit on all public directories to prevent unauthorized and unintended information transferred via shared system resources. prevents CWE-266
  • V-260559 Ubuntu 22.04 LTS must ensure only users who need access to security functions are part of sudo group. prevents CWE-266
Ubuntu 24.04 (2 rules)
  • V-270748 Ubuntu 24.04 LTS must ensure only users who need access to security functions are part of sudo group. prevents CWE-266
  • V-270750 Ubuntu 24.04 LTS must set a sticky bit on all public directories to prevent unauthorized and unintended information transferred via shared system resources. prevents CWE-266
Windows 10 (2 rules)
  • V-220865 The Windows Remote Management (WinRM) service must not use Basic authentication. prevents CWE-693
  • V-220812 Credential Guard must be running on Windows 10 domain-joined systems. prevents CWE-693
Windows Server 2016 (1 rule)
  • V-225012 Windows Server 2016 must be running Credential Guard on domain-joined member servers. prevents CWE-693
Windows Server 2019 (1 rule)
  • V-205907 Windows Server 2019 must be running Credential Guard on domain-joined member servers. prevents CWE-693

References