CVE-2021-29957

CVE-2021-29957 is a medium-severity vulnerability in Mozilla Thunderbird with a CVSS 3.x base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Description

If a MIME encoded email contains an OpenPGP inline signed or encrypted message part, but also contains an additional unprotected part, Thunderbird did not indicate that only parts of the message are protected. This vulnerability affects Thunderbird < 78.10.2.

Frequently asked questions

What is CVE-2021-29957?
If a MIME encoded email contains an OpenPGP inline signed or encrypted message part, but also contains an additional unprotected part, Thunderbird did not indicate that only parts of the message are protected. This vulnerability affects Thunderbird < 78.10.2.
How severe is CVE-2021-29957?
CVE-2021-29957 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2021-29957 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (57th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-29957?
CVE-2021-29957 affects Mozilla Thunderbird. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-29957?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-29957 published?
CVE-2021-29957 was published on 2021-06-24 and last updated on 2026-06-17.

References

Affected products (1)

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