What’s Vulnerable › Vulnerabilities

CVE-2020-12397

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-05-22 · updated 2026-06-17
• Weakness: CWE-346

Description

By encoding Unicode whitespace characters within the From email header, an attacker can spoof the sender email address that Thunderbird displays. This vulnerability affects Thunderbird < 68.8.0.

Affected products

• Canonical Ubuntu Linux: 16.04, 18.04, 19.10, 20.04
• Mozilla Thunderbird: before 68.8.0 — fixed in 68.8.0

How to fix

Upgrade to a fixed version: Mozilla Thunderbird 68.8.0. Check the vendor advisory for mitigations.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1617370
• https://security.gentoo.org/glsa/202005-03
• https://usn.ubuntu.com/4373-1/
• https://www.mozilla.org/security/advisories/mfsa2020-18/
• https://bugzilla.mozilla.org/show_bug.cgi?id=1617370
• https://security.gentoo.org/glsa/202005-03
• https://usn.ubuntu.com/4373-1/
• https://www.mozilla.org/security/advisories/mfsa2020-18/

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