AUGUST 4, 2026
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Case File

CVE-2021-43527

CRITICAL · CVSS 9.8 EPSS 17.56%

Source: NVD + CISA KEV + EPSS (historical backfill) · Published 2021-12-08 · Last synced 2026-08-04

CyberRota Analysis

This is a critical severity vulnerability with a CVSS score of 9.8. It affects Office, Firefox. Its EPSS score suggests a 17.6% probability of exploitation in the next 30 days.

CVE
CVE-2021-43527
Severity
CRITICAL
CVSS
9.8
EPSS
17.56%
Office Firefox

Original NVD Description

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.

Related CVEs

Other vulnerabilities affecting the same vendor(s)