What’s Vulnerable › Vulnerabilities

CVE-2020-15676

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-10-01 · updated 2026-06-17
• Weakness: CWE-79

Description

Firefox sometimes ran the onload handler for SVG elements that the DOM sanitizer decided to remove, resulting in JavaScript being executed after pasting attacker-controlled data into a contenteditable element. This vulnerability affects Firefox < 81, Thunderbird < 78.3, and Firefox ESR < 78.3.

Affected products

• Debian Linux: 9.0, 10.0
• Mozilla Firefox: before 81.0 — fixed in 81.0
• Mozilla Firefox ESR: before 78.3 — fixed in 78.3
• Mozilla Thunderbird: before 78.3 — fixed in 78.3
• openSUSE Leap: 15.1, 15.2

How to fix

Upgrade to a fixed version: Mozilla Firefox 81.0; Mozilla Firefox ESR 78.3; Mozilla Thunderbird 78.3. Check the vendor advisory for mitigations.

References

• http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00074.html
• http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00077.html
• https://bugzilla.mozilla.org/show_bug.cgi?id=1646140
• https://lists.debian.org/debian-lts-announce/2020/10/msg00020.html
• https://security.gentoo.org/glsa/202010-02
• https://www.debian.org/security/2020/dsa-4770
• https://www.mozilla.org/security/advisories/mfsa2020-42/
• https://www.mozilla.org/security/advisories/mfsa2020-43/
• https://www.mozilla.org/security/advisories/mfsa2020-44/
• http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00074.html
• http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00077.html
• https://bugzilla.mozilla.org/show_bug.cgi?id=1646140

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