{"id":"CVE-2021-43527","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-43527","generatedAt":"2026-10-27T21:47:09.594Z","title":"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.","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.","published":"2021-12-08T22:15:09.000Z","lastModified":"2026-06-17T04:11:04.000Z","status":"Modified","sourceIdentifier":"security@mozilla.org","cvss":{"version":"3.1","score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-787"],"affected":["mozilla/nss","mozilla/nss esr","netapp/cloud backup","netapp/e-series santricity os controller","oracle/communications cloud native core binding support function","oracle/communications cloud native core network repository function","oracle/communications cloud native core network slice selection function","oracle/communications policy management","starwindsoftware/starwind san \\& nas","starwindsoftware/starwind virtual san"],"epss":{"score":0.17563,"percentile":0.97119,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"EPSS puts the probability of exploitation in the next 30 days at 17.6%, higher than 97% of all known CVEs. Patch or mitigate before the next change window."},"changes":[],"references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1737470","tags":["Issue Tracking","Permissions Required","Vendor Advisory"],"source":"security@mozilla.org"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-594438.pdf","tags":["Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://ftp.mozilla.org/pub/security/nss/releases/NSS_3_68_1_RTM/","tags":["Vendor Advisory"],"source":"security@mozilla.org"},{"url":"https://ftp.mozilla.org/pub/security/nss/releases/NSS_3_73_RTM/","tags":["Vendor Advisory"],"source":"security@mozilla.org"},{"url":"https://security.gentoo.org/glsa/202212-05","tags":["Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://security.netapp.com/advisory/ntap-20211229-0002/","tags":["Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2021-51/","tags":["Vendor Advisory"],"source":"security@mozilla.org"},{"url":"https://www.oracle.com/security-alerts/cpuapr2022.html","tags":["Patch","Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://www.starwindsoftware.com/security/sw-20220802-0001/","tags":["Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1737470","tags":["Issue Tracking","Permissions Required","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-594438.pdf","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://ftp.mozilla.org/pub/security/nss/releases/NSS_3_68_1_RTM/","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://ftp.mozilla.org/pub/security/nss/releases/NSS_3_73_RTM/","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/202212-05","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20211229-0002/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.mozilla.org/security/advisories/mfsa2021-51/","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpuapr2022.html","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.starwindsoftware.com/security/sw-20220802-0001/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-43527","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}