CVE-2021-43527
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.
Does this matter?
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.
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.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 17.56% probability · 97th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- 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
- Source
- security@mozilla.org
EPSS 17.6% since 26 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1737470Issue Tracking, Permissions Required, Vendor Advisory
- https://cert-portal.siemens.com/productcert/pdf/ssa-594438.pdfThird Party Advisory
- https://ftp.mozilla.org/pub/security/nss/releases/NSS_3_68_1_RTM/Vendor Advisory
- https://ftp.mozilla.org/pub/security/nss/releases/NSS_3_73_RTM/Vendor Advisory
- https://security.gentoo.org/glsa/202212-05Third Party Advisory
- https://security.netapp.com/advisory/ntap-20211229-0002/Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-51/Vendor Advisory
- https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch, Third Party Advisory
- https://www.starwindsoftware.com/security/sw-20220802-0001/Third Party Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1737470Issue Tracking, Permissions Required, Vendor Advisory
- https://cert-portal.siemens.com/productcert/pdf/ssa-594438.pdfThird Party Advisory
- https://ftp.mozilla.org/pub/security/nss/releases/NSS_3_68_1_RTM/Vendor Advisory
- https://ftp.mozilla.org/pub/security/nss/releases/NSS_3_73_RTM/Vendor Advisory
- https://security.gentoo.org/glsa/202212-05Third Party Advisory
- https://security.netapp.com/advisory/ntap-20211229-0002/Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-51/Vendor Advisory
- https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch, Third Party Advisory
- https://www.starwindsoftware.com/security/sw-20220802-0001/Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.