Vulnerability in Mozilla Firefox

CVE-2020-12402

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.

EPSS: 0.003 (26.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.4 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:N/A:N.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2020-12402?
CVE-2020-12402 is a medium-severity vulnerability in Mozilla Firefox, classified under Observable Discrepancy. CVSS score: 4.4/10. Published 2020-07-09.
How severe is CVE-2020-12402?
Medium severity. CVSS v3 base score is 4.4 out of 10.
Is CVE-2020-12402 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.