CVE-2026-92238Network attack vector

Field confusion via malformed mail-header parsing

Published Sep 15, 2026 · Updated Sep 15, 2026

Improper mail-header parsing in Mozilla Thunderbird before 140.16 allows remote attackers to trigger field confusion or memory-safety violations. The mail-header parser accepts maliciously constructed field boundaries and can combine multiple header fields into one parsed value; Mozilla has not disclosed the exact routine or invalid memory operation. Reachability requires Thunderbird to process a crafted message header, and the source record does not specify the operational impact of the memory-safety violation.

CVSS severityUnavailable
Unscored
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper mail-header parsing in Mozilla Thunderbird before 140.16 allows remote attackers to trigger field confusion or memory-safety violations. The mail-header parser accepts maliciously constructed field boundaries and can combine multiple header fields into one parsed value; Mozilla has not disclosed the exact routine or invalid memory operation. Reachability requires Thunderbird to process a crafted message header, and the source record does not specify the operational impact of the memory-safety violation.

The record

CVE
CVE-2026-92238
Published
Sep 15, 2026
Updated
Sep 15, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
Unavailable
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 15, 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

No CVSS assessment is available in this record.

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

No sourced classifications are available.

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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