CVE-2021-23993

Description

An attacker may perform a DoS attack to prevent a user from sending encrypted email to a correspondent. If an attacker creates a crafted OpenPGP key with a subkey that has an invalid self signature, and the Thunderbird user imports the crafted key, then Thunderbird may try to use the invalid subkey, but the RNP library rejects it from being used, causing encryption to fail. This vulnerability affects Thunderbird < 78.9.1.

Category

6.5
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.05%
Vendor Advisory mozilla.org Vendor Advisory mozilla.org
Affected: Mozilla Thunderbird
Published at:
Updated at:

References

Link Tags
https://www.mozilla.org/security/advisories/mfsa2021-13/ release notes vendor advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1666360 issue tracking permissions required vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-23993?
CVE-2021-23993 has been scored as a medium severity vulnerability.
How to fix CVE-2021-23993?
To fix CVE-2021-23993, 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-2021-23993 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-23993 is being actively exploited. 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-2021-23993?
CVE-2021-23993 affects Mozilla Thunderbird.
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