CVE-2021-23991

Public Exploit

Description

If a Thunderbird user has previously imported Alice's OpenPGP key, and Alice has extended the validity period of her key, but Alice's updated key has not yet been imported, an attacker may send an email containing a crafted version of Alice's key with an invalid subkey, Thunderbird might subsequently attempt to use the invalid subkey, and will fail to send encrypted email to Alice. This vulnerability affects Thunderbird < 78.9.1.

6.8

CVSS

Severity: Medium

CVSS 3.1 •

CVSS 2.0 •

EPSS 0.22%

Vendor Advisory mozilla.org Vendor Advisory mozilla.org

Affected: Mozilla Thunderbird

References

Link	Tags
https://www.mozilla.org/security/advisories/mfsa2021-13/	release notes vendor advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1673240	issue tracking exploit vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-23991?: CVE-2021-23991 has been scored as a medium severity vulnerability.
How to fix CVE-2021-23991?: To fix CVE-2021-23991, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-23991 being actively exploited in the wild?: It is possible that CVE-2021-23991 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-23991?: CVE-2021-23991 affects Mozilla Thunderbird.

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