CVE-2026-74939Network attack vector

Privilege escalation via undisclosed DOM navigation flaw

Published Aug 18, 2026 · Updated Aug 21, 2026

Privilege escalation in Mozilla Firefox and Thunderbird allows remote attackers to gain elevated privileges through crafted web content. Mozilla has not published the faulty operation in the DOM Navigation component, and the linked security bug remains access-restricted. Exploitation requires user interaction with browser or browser-like content; Thunderbird disables scripting while reading email, limiting ordinary message-based exposure.

CVSS severity8.8
High
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Privilege escalation in Mozilla Firefox and Thunderbird allows remote attackers to gain elevated privileges through crafted web content. Mozilla has not published the faulty operation in the DOM Navigation component, and the linked security bug remains access-restricted. Exploitation requires user interaction with browser or browser-like content; Thunderbird disables scripting while reading email, limiting ordinary message-based exposure.

The record

CVE
CVE-2026-74939
Published
Aug 18, 2026
Updated
Aug 21, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-269
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-269Improper Privilege Management

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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