CVE-2021-43527: Mozilla Nss

Critical severity, CVSS 9.8. EPSS: 17.6% chance of exploitation in the next 30 days.

NSS (Network Security Services) versions prior to 3.73 or 3.68.1 ESR are vulnerable to a heap overflow when handling DER-encoded DSA or RSA-PSS signatures. Applications using NSS for handling signatures encoded within CMS, S/MIME, PKCS \#7, or PKCS \#12 are likely to be impacted. Applications using NSS for certificate validation or other TLS, X.509, OCSP or CRL functionality may be impacted, depending on how they configure NSS. *Note: This vulnerability does NOT impact Mozilla Firefox.* However, email clients and PDF viewers that use NSS for signature verification, such as Thunderbird, LibreOffice, Evolution and Evince are believed to be impacted. This vulnerability affects NSS < 3.73 and NSS < 3.68.1.

Affected products

• Mozilla Nss: before 3.73 (fixed in 3.73)
• Mozilla Nss ESR: before 3.68.1 (fixed in 3.68.1)
• Netapp Cloud Backup: affected versions not specified
• Netapp E-Series Santricity OS Controller: from 11.0, up to and including 11.70.1
• Oracle Communications Cloud Native Core Binding Support Function: version 1.11.0 only
• Oracle Communications Cloud Native Core Network Repository Function: version 1.15.0 only; version 1.15.1 only
• Oracle Communications Cloud Native Core Network Slice Selection Function: version 1.8.0 only
• Oracle Communications Policy Management: version 12.6.0.0.0 only
• Starwindsoftware Starwind San & NAS: version v8r13 only
• Starwindsoftware Starwind Virtual San: version v8r13 only

Published 2021-12-08. Last modified 2026-06-17.