CVE-2026-12312Network attack vector

Confidential-data exposure via undisclosed memory corruption

Published Jun 16, 2026 · Updated Jun 16, 2026

Memory corruption in Firefox and Thunderbird before 152 and their ESR releases before 140.12 allows remote attackers to expose confidential data. Mozilla has not disclosed the affected component, memory operation, or attacker-controlled input in the public advisories or bug reference. No authentication or user interaction is required; Thunderbird email reading is generally not exposed because scripting is disabled, limiting risk to browser-like contexts.

CVSS severity7.5
High
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in Firefox and Thunderbird before 152 and their ESR releases before 140.12 allows remote attackers to expose confidential data. Mozilla has not disclosed the affected component, memory operation, or attacker-controlled input in the public advisories or bug reference. No authentication or user interaction is required; Thunderbird email reading is generally not exposed because scripting is disabled, limiting risk to browser-like contexts.

The record

CVE
CVE-2026-12312
Published
Jun 16, 2026
Updated
Jun 16, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-119
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 16, 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

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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.

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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-119Improper Restriction of Operations within the Bounds of a Memory Buffer

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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