CVE-2020-6821

When reading from areas partially or fully outside the source resource with WebGL's <code>copyTexSubImage</code> method, the specification requires the returned values be zero. Previously, this memory was uninitialized, leading to potentially sensitive data disclosure. This vulnerability affects Thunderbird < 68.7.0, Firefox ESR < 68.7, and Firefox < 75.

• CWE-908

• https://bugzilla.mozilla.org/show_bug.cgi?id=1625404Issue Tracking, Permissions Required
• https://usn.ubuntu.com/4335-1/Third Party Advisory
• https://www.mozilla.org/security/advisories/mfsa2020-12/Vendor Advisory
• https://www.mozilla.org/security/advisories/mfsa2020-13/Vendor Advisory
• https://www.mozilla.org/security/advisories/mfsa2020-14/Vendor Advisory
• https://bugzilla.mozilla.org/show_bug.cgi?id=1625404Issue Tracking, Permissions Required
• https://usn.ubuntu.com/4335-1/Third Party Advisory
• https://www.mozilla.org/security/advisories/mfsa2020-12/Vendor Advisory
• https://www.mozilla.org/security/advisories/mfsa2020-13/Vendor Advisory
• https://www.mozilla.org/security/advisories/mfsa2020-14/Vendor Advisory

Published

Apr 24, 2020

Last Modified

Jun 17, 2026

Status

Modified

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