Vulnerability record · CVE-2026-92238 · published 15 September 2026

CVE-2026-92238: Mozilla thunderbird http request smuggling vulnerability

Mozilla · Thunderbird

A maliciously constructed mail header could lead to multiple fields being parsed as one, or potential memory safety violations. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.

9.8 CVSS 3.1 Critical EPSS 0.54% · top 56.9% CWE-444 · HTTP request smuggling

9.8CVSS 3.1 base score

0.54%EPSS exploitation probability, 30 days

NoNot in CISA KEV

1Affected product versions listed by NVD

4References

24 Sep 2026Last modified by NVD

Description

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

Thunderbird Mozilla

References

Link	Tags
https://bugzilla.mozilla.org/show_bug.cgi?id=2060601	Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-94/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-95/	Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-96/	Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-92238), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.