CVE-2020-6821: mozilla firefox Use of Uninitialized Resource
Vulnerability summary
CVE-2020-6821 is a high (CVSS 7.5) Use of Uninitialized Resource vulnerability in mozilla firefox. EPSS estimates a 1.50% chance of exploitation in the next 30 days, higher than 73.9% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 27 · Related 13Timeline
- 24-04-2020PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
Description
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.
CVSS metrics
4 scores · 3 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS trend
Probability
1.50%
Chance of exploitation in the next 30 days
Percentile
74%
Versus all other CVEs
30-day change
0.00 pp
From 1.50% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Ubuntu5 products
- firefox< 75.0+build3-0ubuntu0.16.04.1 | < 75.0+build3-0ubuntu0.18.04.1 | < 75.0+build3-0ubuntu1
- mozjs38All versions (No fix recorded)
- mozjs52All versions (No fix recorded)
- mozjs68All versions (No fix recorded)
- thunderbird< 1:68.7.0+build1-0ubuntu0.16.04.2 | < 1:68.7.0+build1-0ubuntu0.18.04.1 | < 1:68.7.0+build1-0ubuntu1
Mozilla3 products
- firefox≥ unspecified, < 75 | < 75.0
- firefox_esr≥ unspecified, < 68.7 | < 68.7.0
- thunderbird≥ unspecified, < 68.7.0 | < 68.7.0
Debian2 products
- firefox-esr< 68.7.0esr-1
- thunderbird< 1:68.7.0-1
3 vendors · 10 products
