Mozilla Network Security Service (NSS): Denial of service

Background

The Mozilla Network Security Service (NSS) is a library implementing security features like SSL v.2/v.3, TLS, PKCS #5, PKCS #7, PKCS #11, PKCS #12, S/MIME and X.509 certificates.

Description

A flaw was found in the way Mozilla Network Security Service (NSS) handled CCS (ChangeCipherSpec) messages in TLS 1.3.

Impact

A remote attacker could send multiple crafted CSS messages in row after ClientHello message to a server application linked against NSS library, possibly resulting in a Denial of Service condition.

Workaround

Disable TLS 1.3 protocol.

Resolution

All NSS users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=dev-libs/nss-3.58"