Debian Security Advisory

DLA-3634-1 nss -- LTS security update

Date Reported:
28 Oct 2023
Affected Packages:
Security database references:
In Mitre's CVE dictionary: CVE-2020-25648, CVE-2023-4421.
More information:

Multiple vulnerabilities were found in nss, a set of libraries designed to support cross-platform development of security-enabled client and server applications.

  • CVE-2020-25648

    A flaw was discovered in how NSS handles CipherChangeSpec messages in TLS 1.3. It could allow an attacker to send multiple CCS messages to servers compiled against NSS, causing denial-of-service.

  • CVE-2023-4421

    A fuzzing project discovered vulnerabilities to Bleichenbacher timing attacks in NSS's facilities for RSA cryptography.

For Debian 10 buster, these problems have been fixed in version 2:3.42.1-1+deb10u7.

We recommend that you upgrade your nss packages.

For the detailed security status of nss please refer to its security tracker page at:

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: