Mozilla Developer Nicolas Silva found that when using WebRender, Firefox would under certain conditions leak arbitrary GPU memory to the vi…

published 2020-07-09 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-4719

cvss: 6.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.0%; EPSS 1.0% chance of exploitation in 30 days, percentile 62%
public exploits: 0; none known

Mozilla Developer Nicolas Silva found that when using WebRender, Firefox would under certain conditions leak arbitrary GPU memory to the visible screen. The leaked memory content was visible to the user, but not observable from web content. This vulnerability affects Firefox < 77.

Patch / fix

fixed in 1 distros 4

Mozilla Firefox 77

ubuntu opensuse alpine arch linux

firefox Ubuntu 16.04 LTS 77.0.1+build1-0ubuntu0.16.04.1
firefox Ubuntu 18.04 LTS 77.0.1+build1-0ubuntu0.18.04.1
firefox Ubuntu 20.04 LTS 77.0.1+build1-0ubuntu0.20.04.1

ubuntu advisories UBUNTU-CVE-2020-12407

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

firefox-esr openSUSE Tumbleweed 128.5.1-1.1
MozillaFirefox openSUSE Tumbleweed 92.0-1.2

opensuse advisories openSUSE-SU-2024:14572-1 openSUSE-SU-2024:10600-1

firefox Alpine 3.23, Alpine 3.22, Alpine 3.21 +9 more 77.0-r0
librewolf Alpine 3.24, Alpine 3.23, Alpine 3.22 +1 more 77.0-r0

alpine advisories ALPINE-CVE-2020-12407

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

firefox Arch Linux 77.0-1

arch linux advisories AVG-1173

Exploit prediction

0.97% chance of exploitation in the next 30 days, higher than 62% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
NVD	2.0	2.6	AV:N/AC:H/Au:N/C:P/I:N/A:N

Affected products

Mozilla Firefox

Classification

Weakness

CWE-125 Out-of-bounds Read

References

mozilla.org /security/advisories/mfsa2020-20/
vendor-advisory
bugzilla.mozilla.org /show_bug.cgi?id=1637112
issue-tracking, permissions-required, vendor-advisory

Sources

CVE List CVE-2020-12407
NVD CVE-2020-12407

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary