CVE-2019-11755

CVE-2019-11755 is a high-severity vulnerability in Mozilla Thunderbird with a CVSS 3.x base score of 7.5. 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-347.

Key facts

Description

A crafted S/MIME message consisting of an inner encryption layer and an outer SignedData layer was shown as having a valid digital signature, although the signer might have had no access to the contents of the encrypted message, and might have stripped a different signature from the encrypted message. Previous versions had only suppressed showing a digital signature for messages with an outer multipart/signed layer. This vulnerability affects Thunderbird < 68.1.1.

Frequently asked questions

What is CVE-2019-11755?
A crafted S/MIME message consisting of an inner encryption layer and an outer SignedData layer was shown as having a valid digital signature, although the signer might have had no access to the contents of the encrypted message, and might have stripped a different signature from the encrypted message. Previous versions had only suppressed showing a digital signature for messages with an outer multipart/signed layer. This vulnerability affects Thunderbird < 68.1.1.
How severe is CVE-2019-11755?
CVE-2019-11755 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2019-11755 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (61st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-11755?
CVE-2019-11755 affects Mozilla Thunderbird. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2019-11755?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2019-11755 published?
CVE-2019-11755 was published on 2019-09-27 and last updated on 2026-06-17.

References

Affected products (1)

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