CVE-2020-24661

Severity: medium (CVSS 5.9 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2020-08-26 · updated 2026-06-17
Weakness: CWE-295

Description

GNOME Geary before 3.36.3 mishandles pinned TLS certificate verification for IMAP and SMTP services using invalid TLS certificates (e.g., self-signed certificates) when the client system is not configured to use a system-provided PKCS#11 store. This allows a meddler in the middle to present a different invalid certificate to intercept incoming and outgoing mail.

Affected products

Fedoraproject Fedora: 31, 32
GNOME Geary: before 3.36.3 — fixed in 3.36.3

How to fix

Upgrade to a fixed version: GNOME Geary 3.36.3. Check the vendor advisory for mitigations.

References

https://gitlab.gnome.org/GNOME/geary/-/issues/866
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/G7OTYTGND6EFOKNQJWCHKKXKSN7SM73Y/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NS6CSTOBVO5HSAR3X5CT6DS6QDHXDB26/
https://tools.cisco.com/security/center/content/CiscoSeg/message/NS6CSTOBVO5HSAR3X5CT6DS6QDHXDB26/
https://gitlab.gnome.org/GNOME/geary/-/issues/866
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/G7OTYTGND6EFOKNQJWCHKKXKSN7SM73Y/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NS6CSTOBVO5HSAR3X5CT6DS6QDHXDB26/
https://tools.cisco.com/security/center/content/CiscoSeg/message/NS6CSTOBVO5HSAR3X5CT6DS6QDHXDB26/

Get alerted when CVE-2020-24661 or the next vulnerability affects your stack