CVE-2020-12389

The Firefox content processes did not sufficiently lockdown access control which could result in a sandbox escape. *Note: this issue only affects Firefox on Windows operating systems.*. This vulnerability affects Firefox ESR < 68.8 and Firefox < 76.

Published: 2020-05-26 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-12389 is rated High Risk (67.1/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 1.73%). EPSS rose +1.06% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-12389

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.67% 1.73% +1.06%
2 2026-05-28 0.56% 0.67% +0.11%
3 2025-11-21 — 0.56% —

Full EPSS history (13 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-12389

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
10.0 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 6.0 [email protected]
7.5 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 6.4 [email protected]

Weakness enumeration for CVE-2020-12389

OS Trackers for CVE-2020-12389

vendor priority summary link
alpine critical CVE-2020-12389: 3 source package rows (firefox, firefox-esr, librewolf); 17 state rows across 7 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 17, open 0. https://security.alpinelinux.org/vuln/CVE-2020-12389
debian unimportant CVE-2020-12389 unimportant priority: Debian including 2 source packages (firefox, firefox-esr), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 6. https://security-tracker.debian.org/tracker/CVE-2020-12389
redhat high — https://access.redhat.com/security/cve/CVE-2020-12389
suse high CVE-2020-12389 severity important: SUSE including 53 source package names (MozillaFirefox-102.11.0-150200.152.87.1, MozillaFirefox-115.10.0-150200.152.134.1, …), 120 product×package rows across 40 product lines (HPE Helion OpenStack 8, SUSE Enterprise Storage 5, … (40 product lines)): Fixed 120. https://www.suse.com/security/cve/CVE-2020-12389/
ubuntu medium CVE-2020-12389 medium priority: Ubuntu including 5 source packages (firefox, mozjs38, mozjs52, mozjs60, mozjs68), 70 status rows across 14 suites (bionic, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, trusty, upstream, xenial): DNE 46, ignored 12, not-affected 11, released 1. https://ubuntu.com/security/CVE-2020-12389

Affected software / configurations for CVE-2020-12389

Vendor Product Version Raw CPE
mozilla firefox < 76.0 cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
mozilla firefox_esr < 68.8.0 cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*

References for CVE-2020-12389

cvelogic Threat Intelligence