CVE-2026-84125Network attack vector

Memory corruption via DOM use-after-free

Published Sep 1, 2026 · Updated Sep 1, 2026

Use-after-free in Mozilla Firefox and Thunderbird allows remote attackers to corrupt process memory through crafted web content. Mozilla identifies the locus as DOM Core & HTML, but the referenced bug is access-controlled and no public source names the freed object or stale-pointer operation. Processing content that reaches this component requires user interaction; public material does not establish code execution, sandbox escape, or a narrower consequence.

CVSS severity5.4
Medium
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Mozilla Firefox and Thunderbird allows remote attackers to corrupt process memory through crafted web content. Mozilla identifies the locus as DOM Core & HTML, but the referenced bug is access-controlled and no public source names the freed object or stale-pointer operation. Processing content that reaches this component requires user interaction; public material does not establish code execution, sandbox escape, or a narrower consequence.

The record

CVE
CVE-2026-84125
Published
Sep 1, 2026
Updated
Sep 1, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-416, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 1, 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

5.4CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

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-416Use After Free
T1203Exploitation for Client Execution

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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