Observable discrepancy in Mozilla Firefox
Priority LOW 20CWE-203Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- Required
- Attack complexity
- High
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Partial Red Hat: 9 fixed, 2 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-203.
Summary
During RSA key generation, bignum implementations used a variation of the Binary Extended Euclidean Algorithm which entailed significantly input-dependent flow. This allowed an attacker able to perform electromagnetic-based side channel attacks to record traces leading to the recovery of the secret primes. *Note:* An unmodified Firefox browser does not generate RSA keys in normal operation and is not affected, but products built on top of it might. This vulnerability affects Firefox < 78.
Why it matters now
EPSS 0.00337 27th percentileScored 2026-11-07
Fix Partial Firefox (Mozilla): 78Red Hat: 3 advisoriesRed Hat: 9 fixed, 2 without a fix
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Mozilla | Firefox | before 78 | 78 | Patch available | CNA |
- Firefox VendorMozilla Affected before 78 Fixed in 78 Patch available CNA
CPE configurations NVD · 5
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* | before 78.0 | Vulnerable | Mozilla |
| cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* | 32 | Vulnerable | Fedoraproject |
| cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:* | 15.1 | Vulnerable | openSUSE |
| cpe:2.3:o:opensuse:leap:15.2:*:*:*:*:*:*:* | 15.2 | Vulnerable | openSUSE |
| cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* | 9.0 | Vulnerable | Debian |
- cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* Versions before 78.0 Vulnerable ·Mozilla
- cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* Versions 32 Vulnerable ·Fedoraproject
- cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:* Versions 15.1 Vulnerable ·openSUSE
- cpe:2.3:o:opensuse:leap:15.2:*:*:*:*:*:*:* Versions 15.2 Vulnerable ·openSUSE
- cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Debian
Remediation
- Fix · CNA Firefox (Mozilla) Fixed in 78
Red Hat 3 advisories
- RHSA-2021:0949 Released 2021-03-22 · Red Hat rating LowRed Hat OpenShift Do openshift/odo-init-image 1.1.3 security update
- OpenShift Do 1 openshiftdo/odo-init-image-rhel7
- RHSA-2020:4076 Released 2020-09-29 · Red Hat rating Moderatenss and nspr security, bug fix, and enhancement update
- Red Hat Enterprise Linux Client (v. 7) nspr-4.25.0-2.el7_9, nss-3.53.1-3.el7_9, nss-softokn-3.53.1-6.el7_9 +4
- Red Hat Enterprise Linux Client Optional (v. 7) nspr-devel-4.25.0-2.el7_9, nss-devel-3.53.1-3.el7_9, nss-pkcs11-devel-3.53.1-3.el7_9 +3
- Red Hat Enterprise Linux ComputeNode Optional (v. 7) nspr-devel-4.25.0-2.el7_9, nss-devel-3.53.1-3.el7_9, nss-pkcs11-devel-3.53.1-3.el7_9 +3
- Red Hat Enterprise Linux Server (v. 7) nspr-4.25.0-2.el7_9, nspr-4.25.0-2.el7_9.ppc, nspr-devel-4.25.0-2.el7_9 +19
- Red Hat Enterprise Linux Server Optional (v. 7) nss-pkcs11-devel-3.53.1-3.el7_9, nss-pkcs11-devel-3.53.1-3.el7_9.ppc
- Red Hat Enterprise Linux Workstation (v. 7) nspr-4.25.0-2.el7_9, nspr-devel-4.25.0-2.el7_9, nss-3.53.1-3.el7_9 +9
- Red Hat Enterprise Linux Workstation Optional (v. 7) nss-pkcs11-devel-3.53.1-3.el7_9
- RHSA-2020:3280 Released 2020-08-03 · Red Hat rating Moderatenss and nspr security, bug fix, and enhancement update
- Red Hat Enterprise Linux AppStream (v. 8) nspr-4.25.0-2.el8_2, nspr-devel-4.25.0-2.el8_2, nss-3.53.1-11.el8_2 +9
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Advisory ·
Mozilla Firefox — openSUSE-SU-2020:0983
13 records Highest priority Priority MEDIUM 6 MEDIUM, 7 LOW
Other records, highest priority first
- TI-2020-09937 Use after free in Mozilla Firefox ESRPriority MEDIUM 43
- TI-2020-09935 Reachable assertion in Mozilla Firefox ESRPriority MEDIUM 43
- TI-2020-09940 Out-of-bounds write in Mozilla FirefoxPriority MEDIUM 42
- Advisory ·
Mozilla Firefox — openSUSE-SU-2020:1017
13 records Highest priority Priority MEDIUM 6 MEDIUM, 7 LOW
Other records, highest priority first
- TI-2020-09937 Use after free in Mozilla Firefox ESRPriority MEDIUM 43
- TI-2020-09935 Reachable assertion in Mozilla Firefox ESRPriority MEDIUM 43
- TI-2020-09940 Out-of-bounds write in Mozilla FirefoxPriority MEDIUM 42
Show 1 more group
- Advisory ·
Mozilla Firefox — GLSA-202007-10
12 records Highest priority Priority MEDIUM 6 MEDIUM, 6 LOW
Other records, highest priority first
- TI-2020-09937 Use after free in Mozilla Firefox ESRPriority MEDIUM 43
- TI-2020-09935 Reachable assertion in Mozilla Firefox ESRPriority MEDIUM 43
- TI-2020-09940 Out-of-bounds write in Mozilla FirefoxPriority MEDIUM 42
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 5 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| OpenShift Do 1 | Fixed | RHSA-2021:0949 |
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2020:3280 |
| Red Hat Enterprise Linux Client (v. 7) | Fixed | RHSA-2020:4076 |
| Red Hat Enterprise Linux Client Optional (v. 7) | Fixed | RHSA-2020:4076 |
| Red Hat Enterprise Linux ComputeNode Optional (v. 7) | Fixed | RHSA-2020:4076 |
| Red Hat Enterprise Linux Server (v. 7) | Fixed | RHSA-2020:4076 |
| Red Hat Enterprise Linux Server Optional (v. 7) | Fixed | RHSA-2020:4076 |
| Red Hat Enterprise Linux Workstation (v. 7) | Fixed | RHSA-2020:4076 |
| Red Hat Enterprise Linux Workstation Optional (v. 7) | Fixed | RHSA-2020:4076 |
Not affected: 1 product
- Red Hat OpenShift Container Platform 4
Timeline
- 2026-10-02 Threatist record created from CVE-2020-12402
- 2026-10-03 Alias added: GHSA-p7qx-fg8r-mfq9
References
Advisory 13
- https://www.mozilla.org/security/advisories/mfsa2020-24/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1631597
- openSUSE-SU-2020:0953
- openSUSE-SU-2020:0955
- USN-4417-1
- openSUSE-SU-2020:0983
- DSA-4726
- FEDORA-2020-3ef1937475
- openSUSE-SU-2020:1017
- GLSA-202007-10
- USN-4417-2
- FEDORA-2020-16741ac7ff
- [debian-lts-announce] 20200929 [SECURITY] [DLA 2388-1] nss security update
More Mozilla Firefox vulnerabilities
- TI-2024-08981 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.8
- TI-2022-09832 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.6
- TI-2019-08769 Improper input validation in Mozilla Firefox ESR KEVCVSS 3.1CRITICAL 10.0
- TI-2010-03577 Mozilla Firefox 3.5.x through 3.5.14 and 3.6.x through 3.6.11, Thunderbird 3.1.6 before… KEVCVSS 3.1CRITICAL 9.8
- TI-2023-04799 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
- TI-2023-04477 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
Sources
- CVE-2020-12402 · CVE Program
- CVE-2020-12402 · NVD
- FIRST EPSS
- GHSA-p7qx-fg8r-mfq9 · GitHub Advisory Database · CC BY 4.0
- CVE-2020-12402 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences