CVE-2020-12402: During RSA key generation, bignum implementations used a variation of the Binary Extended Euclidean Algorithm which entailed significantly i
Noroxi assessment
Priority: Monitor (action score 17/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.33% (FIRST EPSS).
- Someone with local access to the system can trigger it. A low-privileged account is enough. A user must open a link or visit a page. Special conditions such as timing or configuration are required.
- Fixed version: firefox (Alpine:v3.12) 78.0-r0; nss (Alpine:v3.12) 3.53.1-r0; librewolf (Alpine:v3.21) 78.0-r0.
Low priority for now. Upgrade to firefox (Alpine:v3.12) 78.0-r0; nss (Alpine:v3.12) 3.53.1-r0; librewolf (Alpine:v3.21) 78.0-r0 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
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.
- BDU:2020-04504
- DLA-2266-1
- DLA-2388-1
- DSA-4726-1
- openSUSE-SU-2020:0953-1
- openSUSE-SU-2020:0955-1
- openSUSE-SU-2020:0983-1
- openSUSE-SU-2020:1017-1
- openSUSE-SU-2024:11058-1
- RHSA-2020:3280
- RHSA-2020:4076
- RLSA-2020:3280
- SUSE-SU-2020:14418-1
- SUSE-SU-2020:14421-1
- SUSE-SU-2020:1839-1
- SUSE-SU-2020:1850-1
- SUSE-SU-2020:1898-1
- SUSE-SU-2020:1899-1
- Published
- Jul 9, 2020
- Updated
- Jun 16, 2026
- EPSS
- 0.3% · 27th percentile
- CWE
- CWE-203
Report tools
Action score
17
Monitor
Low priority for now.
- CVSS
- 17 / 40 · 4.4 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| mozilla | firefox | cpe:2.3:a:mozilla:firefox |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
| opensuse | leap | cpe:2.3:o:opensuse:leap |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- debian debian linux9.0
- fedoraproject fedora32
- mozilla firefoxbefore 78.0
- opensuse leap15.1
- opensuse leap15.2
Versions reported by the vendor
Affected version ranges reported by the assigning authority (mozilla). Independent of NVD's CPE analysis and usually ahead of it.
Mozilla Firefox
- unspecified and later · before 78affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.12 | firefox | before 78.0-r0 | 78.0-r0 |
| Alpine:v3.12 | nss | before 3.53.1-r0 | 3.53.1-r0 |
| Alpine:v3.21 | librewolf | before 78.0-r0 | 78.0-r0 |
| Debian:10 | nss | before 2:3.42.1-1+deb10u3 | 2:3.42.1-1+deb10u3 |
| Debian:12 | nss | before 2:3.53.1-1 | 2:3.53.1-1 |
| Debian:8 | nss | before 2:3.26-1+debu8u11 | 2:3.26-1+debu8u11 |
| Debian:9 | nss | before 2:3.26.2-1.1+deb9u2 | 2:3.26.2-1.1+deb9u2 |
| openSUSE:Leap 15.1 | mozilla-nss | before 3.53.1-lp151.2.26.1 | 3.53.1-lp151.2.26.1 |
| openSUSE:Leap 15.1 | MozillaFirefox | before 78.0.1-lp151.2.53.1 | 78.0.1-lp151.2.53.1 |
| openSUSE:Leap 15.2 | mozilla-nss | before 3.53.1-lp152.2.4.1 | 3.53.1-lp152.2.4.1 |
| openSUSE:Leap 15.2 | MozillaFirefox | before 78.0.1-lp152.2.5.1 | 78.0.1-lp152.2.5.1 |
| openSUSE:Tumbleweed | mozilla-nss | before 3.69.1-1.2 | 3.69.1-1.2 |
| Red Hat:enterprise_linux:7::client | nspr | before 0:4.25.0-2.el7_9 | 0:4.25.0-2.el7_9 |
| Red Hat:enterprise_linux:7::client | nspr-debuginfo | before 0:4.25.0-2.el7_9 | 0:4.25.0-2.el7_9 |
| Red Hat:enterprise_linux:7::client | nspr-devel | before 0:4.25.0-2.el7_9 | 0:4.25.0-2.el7_9 |
| Red Hat:enterprise_linux:7::client | nss | before 0:3.53.1-3.el7_9 | 0:3.53.1-3.el7_9 |
| Red Hat:enterprise_linux:7::client | nss-debuginfo | before 0:3.53.1-3.el7_9 | 0:3.53.1-3.el7_9 |
| Red Hat:enterprise_linux:7::client | nss-devel | before 0:3.53.1-3.el7_9 | 0:3.53.1-3.el7_9 |
| Red Hat:enterprise_linux:7::client | nss-pkcs11-devel | before 0:3.53.1-3.el7_9 | 0:3.53.1-3.el7_9 |
| Red Hat:enterprise_linux:7::client | nss-softokn | before 0:3.53.1-6.el7_9 | 0:3.53.1-6.el7_9 |
| Red Hat:enterprise_linux:7::client | nss-softokn-debuginfo | before 0:3.53.1-6.el7_9 | 0:3.53.1-6.el7_9 |
| Red Hat:enterprise_linux:7::client | nss-softokn-devel | before 0:3.53.1-6.el7_9 | 0:3.53.1-6.el7_9 |
| Red Hat:enterprise_linux:7::client | nss-softokn-freebl | before 0:3.53.1-6.el7_9 | 0:3.53.1-6.el7_9 |
| Red Hat:enterprise_linux:7::client | nss-softokn-freebl-devel | before 0:3.53.1-6.el7_9 | 0:3.53.1-6.el7_9 |
+38
Same product
mozilla: all recordsOther highest-scoring records for the same primary product.
- CVE-2010-3765Mozilla Firefox 3.5.x through 3.5.14 and 3.6.x through 3.6.11, Thunderbird 3.1.6 before 3.1.6 and 3.0.x before 3.0.10, and SeaMonkey 2.x befKEV94Now
- CVE-2019-11708Insufficient vetting of parameters passed with the Prompt:Open IPC message between child and parent processes can result in the non-sandboxeKEV87Now
- CVE-2015-4495The PDF reader in Mozilla Firefox before 39.0.3, Firefox ESR 38.x before 38.1.1, and Firefox OS before 2.2 allows remote attackers to bypassKEV86Now
Published before and after this one in the same product
- ← EarlierCVE-2020-12424Jul 9, 2020 · When constructing a permission prompt for WebRTC, a URI was supplied from the content process.26Monitor
- ← EarlierCVE-2020-12399Jul 9, 2020 · NSS has shown timing differences when performing DSA signatures, which was exploitable and could eventually leak private keys.17Monitor
- Later →CVE-2020-12405Jul 9, 2020 · When browsing a malicious page, a race condition in our SharedWorkerService could occur and lead to a potentially exploitable crash.21Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| alpine:firefox | 78.0-r0 · Alpine:v3.12 | Package registry (OSV) |
| alpine:librewolf | 78.0-r0 · Alpine:v3.21 | Package registry (OSV) |
| alpine:nss | 3.53.1-r0 · Alpine:v3.12 | Package registry (OSV) |
| debian:nss | 2:3.53.1-1 · Debian:12 | Package registry (OSV) |
| opensuse:mozilla-nss | 3.53.1-lp151.2.26.1 · openSUSE:Leap 15.1 | Package registry (OSV) |
| opensuse:MozillaFirefox | 78.0.1-lp152.2.5.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| red hat:nspr | 0:4.25.0-2.el8_2 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:nspr-debuginfo | 0:4.25.0-2.el8_2 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:nspr-debugsource | 0:4.25.0-2.el8_2 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:nspr-devel | 0:4.25.0-2.el8_2 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:nss | 0:3.53.1-11.el8_2 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:nss-debuginfo | 0:3.53.1-11.el8_2 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:nss-debugsource | 0:3.53.1-11.el8_2 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:nss-devel | 0:3.53.1-11.el8_2 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:nss-softokn | 0:3.53.1-11.el8_2 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:nss-softokn-debuginfo | 0:3.53.1-11.el8_2 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:nss-softokn-devel | 0:3.53.1-11.el8_2 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:nss-softokn-freebl | 0:3.53.1-11.el8_2 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| rocky linux:nspr | 0:4.25.0-2.el8_2 · Rocky Linux:8 | Package registry (OSV) |
| suse:mozilla-nspr | 4.25-29.12.2 · SUSE:Linux Enterprise Server 11 SP4-LTSS | Package registry (OSV) |
| suse:mozilla-nss | 3.53.1-38.23.1 · SUSE:Linux Enterprise Server 11 SP4-LTSS | Package registry (OSV) |
| suse:MozillaFirefox | 78.0.1-78.80.2 · SUSE:Linux Enterprise Server 11 SP4-LTSS | Package registry (OSV) |
| suse:MozillaFirefox-branding-SLE | 78-4.14.1 · SUSE:Linux Enterprise Module for Desktop Applications 15 SP1 | Package registry (OSV) |
| suse:MozillaFirefox-branding-SLED | 78-21.12.1 · SUSE:Linux Enterprise Server 11 SP4-LTSS | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
No history yet (it accumulates with the daily EPSS job).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- A low-privileged account is enough.
- A user must open a link or visit a page.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- high · data can be read
- Integrity
- none
- Availability
- none
- Attack vector
- Local
- Attack complexity
- High
- Privileges required
- Low
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- None
- Availability impact
- None
Weakness class (CWE)
CWE-203 · Observable DiscrepancyCVSS vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:N/A:N
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (12 more)Show less
- lists.opensuse.org/opensuse-security-announce/2020-07/msg00018.html
- lists.opensuse.org/opensuse-security-announce/2020-07/msg00027.html
- lists.opensuse.org/opensuse-security-announce/2020-07/msg00049.html
- bugzilla.mozilla.org/show_bug.cgi?id=1631597
- lists.debian.org/debian-lts-announce/2020/09/msg00029.html
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RFL6UNFK4MG2WDXLMLFAEIUSM5EUK7CG/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UWVDJRARXNWWWTCGMM63EXLQHH2LNOXO/
- security.gentoo.org/glsa/202007-10
- usn.ubuntu.com/4417-1/
- usn.ubuntu.com/4417-2/
- www.debian.org/security/2020/dsa-4726
- www.mozilla.org/security/advisories/mfsa2020-24/
Vendor advisories and official records. Exploit/PoC links are deliberately left out.