CVE-2019-11727: Mozilla Firefox

Medium severity, CVSS 5.3. EPSS: 1.8% chance of exploitation in the next 30 days.

A vulnerability exists where it possible to force Network Security Services (NSS) to sign CertificateVerify with PKCS#1 v1.5 signatures when those are the only ones advertised by server in CertificateRequest in TLS 1.3. PKCS#1 v1.5 signatures should not be used for TLS 1.3 messages. This vulnerability affects Firefox < 68.

Affected products

• Mozilla Firefox: before 68.0 (fixed in 68.0)

Published 2019-07-23. Last modified 2026-06-17.