How severe is CVE-2026-92238?

CVE-2026-92238 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-92238 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-92238?

CVE-2026-92238 affects Mozilla Thunderbird. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-92238?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-92238 published?

CVE-2026-92238 was published on 2026-09-15 and last updated on 2026-09-24.

CVE-2026-92238

CVE-2026-92238 is a critical-severity vulnerability in Mozilla Thunderbird with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-444.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 1% (44th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-444
Affected product: Mozilla Thunderbird
Published: 2026-09-15
Last modified: 2026-09-24

Description

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.

Frequently asked questions

What is CVE-2026-92238?: 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.
How severe is CVE-2026-92238?: CVE-2026-92238 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-92238 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-92238?: CVE-2026-92238 affects Mozilla Thunderbird. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-92238?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-92238 published?: CVE-2026-92238 was published on 2026-09-15 and last updated on 2026-09-24.

References

Affected products (1)

cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*

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