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Red Hat EUVDEUVD-2026-14849

| CVE-2026-4717 CRITICAL
2026-03-24 mozilla GHSA-pqfx-cwf8-965q
Privilege Escalation Red Hat Mozilla Suse
Critical
Disputed · 9.8 NVD
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Send crafted network request to Netmonitor component
  2. Exploit
    Bypass authentication checks
  3. Execution
    Escalate privileges to system level
  4. Impact
    Execute arbitrary code with elevated permissions

Vulnerability Assessment

Exploitation Conditions

Firefox browser versions < 149 (or Firefox ESR < 140.9) with Netmonitor component accessible. Remote unauthenticated attacker can exploit via network. No victim interaction required. Affects all default Firefox installations.
Impact

Without CVSS scores, EPSS data, or KEV status in the available intelligence, the real-world risk must be inferred from contextual factors. Privilege escalation vulnerabilities in widely-deployed browsers like Firefox present significant risk due to the software's ubiquity and the impact of successful exploitation. The attack vector and complexity remain unknown, but Netmonitor is a developer-facing feature, potentially limiting the attack surface to scenarios where attackers can induce developers to interact with malicious content. The existence of Mozilla security advisories (MFSA2026-20 and MFSA2026-22) indicates formal remediation was provided, suggesting the vendor assessed this as material enough for coordinated disclosure. Without POC or active exploitation data, this appears to be a legitimate but not actively weaponized threat at the time of disclosure.
Exploit ScenarioDerived

A threat actor could craft a malicious webpage or developer script that, when loaded by a Firefox user with developer tools open, exploits the Netmonitor privilege escalation to execute arbitrary code with elevated privileges. Alternatively, a compromised browser extension or local attacker with limited privileges could leverage the vulnerability to gain system-level access. The actual feasibility depends on whether the vulnerability requires user interaction (e.g., opening Developer Tools) or can be triggered automatically, which is not specified in available intelligence.
Act Now Prioritize within 24-48h. Why: CRITICAL severity.
Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 24, 2026

Firefox's Netmonitor component contains a privilege escalation vulnerability that affects versions prior to 149 (ESR < 140.9), allowing unauthenticated attackers to gain elevated privileges through network-accessible attack vectors with no user interaction required. This critical flaw (CVSS 9.8) enables complete system compromise including confidentiality, integrity, and availability violations, with no patch currently available.

Earlier versions of this analysis (1)
v1 Mar 24, 2026 - 12:45 CVSS 9.8

A privilege escalation vulnerability exists in the Netmonitor component of Mozilla Firefox and Firefox ESR, allowing attackers to gain elevated privileges on affected systems. Firefox versions prior to 149 and Firefox ESR versions prior to 140.9 are vulnerable. An attacker exploiting this vulnerability could potentially escalate their privileges to execute code with elevated permissions, though active exploitation status and proof-of-concept availability are not confirmed in available intelligence.

RemediationAI

Immediately upgrade Mozilla Firefox to version 149 or later, and Firefox ESR to version 140.9 or later. Users should visit https://www.mozilla.org/security/advisories/mfsa2026-20/ and https://www.mozilla.org/security/advisories/mfsa2026-22/ for official patching guidance and download links. For environments where immediate patching is not feasible, restrict access to the Firefox Developer Tools (Netmonitor specifically) via group policy or security policies, and educate users to avoid opening untrusted developer consoles or network monitoring interfaces. Enterprise deployments should prioritize patching given the privilege escalation nature of the flaw and the broad exposure of Firefox across user populations.

Affected VersionsENISA

Firefox unspecified <149
Firefox ESR unspecified <140.9

Affected Packages

euvd firefox_esr_unspecified fix: 140.9
euvd firefox_unspecified fix: 149

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 2 packages in euvd

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Technical ContextAI · show details

The vulnerability resides in the Netmonitor debugging component of Firefox, a built-in developer tool used for monitoring network traffic. The affected products are identified via CPE strings cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* and cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*, covering all versions below the patched thresholds. While the specific CWE is not disclosed in available intelligence, privilege escalation vulnerabilities in browser debugging tools typically stem from improper access controls, insufficient input validation, or unsafe inter-process communication (IPC) mechanisms that allow lower-privileged contexts to interact with higher-privileged browser processes.

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Severity by source

Sources disagree (Medium–Critical)
NVD PRIMARY 9.8 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SUSE CRITICAL
Red Hat 6.1 MEDIUM

vuln.today treats the vendor’s rating as authoritative. A higher third-party CVSS (e.g. CISA-ADP) is shown for transparency but does not drive the headline severity.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

2
Patch released
Mar 31, 2026 - 21:13 nvd
Patch available
CVE Published
Mar 24, 2026 - 12:30 nvd
CRITICAL 9.8

DescriptionCVE.org

Privilege escalation in the Netmonitor component. This vulnerability affects Firefox < 149 and Firefox ESR < 140.9.

Executive ViewAI

Why It Matters

Organizations using the Netmonitor component. This vulnerability affects Firefox face critical risk from CVE-2026-4717 rated CVSS 9.8. Successful exploitation could critically impact the confidentiality, integrity, and availability of affected systems. Organizations should apply vendor updates immediately when available and implement compensating controls in the interim.

Business Impact: Severe
Compensating Controls

Apply vendor patch. If immediate patching is not feasible: (1) Implement network-level access controls to limit exposure; (2) Enable enhanced monitoring and alerting; (3) Apply principle of least privilege.

Threat Intelligence Overview

EPSS Score
0.0%
Top 95% exploitable
Data Quality
6 sources
Confidence: High
EUVD NVD CVE.org EPSS Vulnrichment Vendor VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC No
EPSS 0.0%
Patch available Yes
Active threat No
Deciding rule
CRITICAL severity
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Out-of-Cycle
Exploitation
None
System Exposure· derived
Open
Automatable
Yes
Human Impact
Very High
Technical Impact
Total

Priority Score

49
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +49
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Privilege Escalation HIGH

Privilege escalation occurs when an attacker leverages flaws in access control mechanisms to gain permissions beyond what they were originally granted.

Related Vulnerabilities in Firefox Multiple Memory and Boundary Vulnerabilities

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CVE-2026-4704 HIGH
7.5
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7.5
CVE-2026-4707 HIGH
7.5
CVE-2026-4709 HIGH
7.5
CVE-2026-4710 CRITICAL
9.8
CVE-2026-4711 CRITICAL
9.8
CVE-2026-4723 CRITICAL
9.8

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CVE-2013-0757 CRITICAL POC
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CVE-2014-1510 CRITICAL POC
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CVE-2014-1511 CRITICAL POC
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Same technique Privilege Escalation

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Vendor StatusVendor

Debian

firefox
Release Status Fixed Version Urgency
sid vulnerable 148.0.2-1 -
(unstable) fixed (unfixed) -
firefox-esr
Release Status Fixed Version Urgency
bullseye vulnerable 115.14.0esr-1~deb11u1 -
bullseye (security) vulnerable 140.8.0esr-1~deb11u1 -
bookworm vulnerable 128.14.0esr-1~deb12u1 -
bookworm (security) vulnerable 140.8.0esr-1~deb12u1 -
trixie (security), trixie vulnerable 140.8.0esr-1~deb13u1 -
forky, sid vulnerable 140.8.0esr-1 -
(unstable) fixed (unfixed) -

SUSE

Severity: Critical
Product Status
Image SLES15-SP5-SAP-Azure-LI-BYOS Image SLES15-SP5-SAP-Azure-LI-BYOS-Production Image SLES15-SP5-SAP-Azure-VLI-BYOS Image SLES15-SP5-SAP-Azure-VLI-BYOS-Production Image SLES15-SP6-SAP-Azure-LI-BYOS Image SLES15-SP6-SAP-Azure-LI-BYOS-Production Image SLES15-SP6-SAP-Azure-VLI-BYOS Image SLES15-SP6-SAP-Azure-VLI-BYOS-Production Image SLES15-SP7-SAP-Azure-LI-BYOS-Production Image SLES15-SP7-SAP-Azure-VLI-BYOS-Production Affected
SUSE Liberty Linux 10 Fixed
SUSE Liberty Linux 8 Fixed
SUSE Liberty Linux 9 Fixed
SUSE Linux Enterprise Desktop 15 SP7 SUSE Linux Enterprise Server 15 SP7 SUSE Linux Enterprise Server for SAP Applications 15 SP7 Fixed

References

Advisories & patches
ADVISORY https://access.redhat.com/errata/RHSA-2026:5930 ADVISORY https://access.redhat.com/errata/RHSA-2026:5931 ADVISORY https://access.redhat.com/errata/RHSA-2026:5932 ADVISORY https://access.redhat.com/errata/RHSA-2026:6188 ADVISORY https://access.redhat.com/errata/RHSA-2026:6342 ADVISORY https://access.redhat.com/errata/RHSA-2026:6917 ADVISORY https://access.redhat.com/errata/RHSA-2026:7837 ADVISORY https://access.redhat.com/errata/RHSA-2026:7838 ADVISORY https://access.redhat.com/errata/RHSA-2026:7839 ADVISORY https://access.redhat.com/errata/RHSA-2026:7840 ADVISORY https://access.redhat.com/errata/RHSA-2026:7841 ADVISORY https://access.redhat.com/errata/RHSA-2026:7842 ADVISORY https://access.redhat.com/errata/RHSA-2026:7843 ADVISORY https://access.redhat.com/errata/RHSA-2026:7845 ADVISORY https://access.redhat.com/errata/RHSA-2026:7858 ADVISORY https://access.redhat.com/errata/RHSA-2026:8284 ADVISORY https://access.redhat.com/errata/RHSA-2026:8285 ADVISORY https://access.redhat.com/errata/RHSA-2026:8286 ADVISORY https://access.redhat.com/errata/RHSA-2026:8287 ADVISORY https://access.redhat.com/errata/RHSA-2026:8288 ADVISORY https://access.redhat.com/errata/RHSA-2026:8289 ADVISORY https://access.redhat.com/errata/RHSA-2026:8290 ADVISORY https://access.redhat.com/errata/RHSA-2026:8315 ADVISORY https://access.redhat.com/errata/RHSA-2026:8427 ADVISORY https://nvd.nist.gov/vuln/detail/CVE-2026-4717 ADVISORY https://vuldb.com/?id.352765 ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:1126/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:1127/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:1163/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:20978/ REF https://bugzilla.mozilla.org/show_bug.cgi?id=2021695 REF https://www.mozilla.org/security/advisories/mfsa2026-20/ REF https://www.mozilla.org/security/advisories/mfsa2026-22/ REF https://www.mozilla.org/security/advisories/mfsa2026-23/ REF https://www.mozilla.org/security/advisories/mfsa2026-24/

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