cbcvebase.
CVE-2021-43527
published 2021-12-08

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…

PriorityP265critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
EPSS
17.56%
96.8th percentile
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

27 ranges· showing 25
VendorProductVersion rangeFixed in
debiannss< nss 2:3.73-1 (bookworm)nss 2:3.73-1 (bookworm)
debianthunderbird< thunderbird 1:91.3.0-1 (bookworm)thunderbird 1:91.3.0-1 (bookworm)
googlechrome_chrome
mozillafirefox
mozillanss< 3.733.73
mozillanss>= 0 < 2:3.61-1+deb11u12:3.61-1+deb11u1
mozillanss>= 0 < 2:3.73-12:3.73-1
mozillanss>= 0 < 2:3.73-12:3.73-1
mozillanss>= 0 < 2:3.73-12:3.73-1
mozillanss_esr< 3.68.13.68.1
mozillathunderbird< 91.3.091.3.0
mozillathunderbird>= 0 < 1:91.4.1-1~deb11u11:91.4.1-1~deb11u1
mozillathunderbird>= 0 < 1:91.3.0-11:91.3.0-1
mozillathunderbird>= 0 < 1:91.3.0-11:91.3.0-1
mozillathunderbird>= 0 < 1:91.3.0-11:91.3.0-1
mozillathunderbird>= unspecified < 91.3.091.3.0
msrccbl2_nss_3.75-1_on_cbl_mariner_2.0
msrccm1_nss_3.73-1_on_cbl_mariner_1.0
netappe-series_santricity_os_controller11.0 – 11.70.1
oraclecommunications_cloud_native_core_binding_support_function
oraclecommunications_cloud_native_core_network_repository_function
oraclecommunications_cloud_native_core_network_repository_function
oraclecommunications_cloud_native_core_network_slice_selection_function
oraclecommunications_policy_management
paloaltopan-os

Detection & IOCsextracted from sources · hover to see the quote

  • Heap overflow is triggered during DER-encoded DSA or RSA-PSS signature verification in NSS; monitor for crashes or memory corruption in NSS-linked processes (e.g., Thunderbird, LibreOffice, Evolution, Evince) during certificate/signature validation
  • Attack vector includes TLS handshake: an attacker posing as an SSL/TLS server can trigger the flaw in a client application compiled with NSS; also triggerable via a malicious client certificate sent to an NSS-compiled server
  • S/MIME email parsing is an attack surface: Thunderbird is affected when parsing email with an S/MIME signature; flag anomalous S/MIME-signed emails delivered to NSS-linked mail clients
  • Vulnerable code path is in the decodeECorDsaSignature function within NSS; look for crash dumps or stack traces referencing this function in NSS-linked applications
  • Firefox is NOT vulnerable (uses mozilla::pkix for certificate verification); do not conflate Firefox crashes with this CVE — focus detection on Thunderbird, LibreOffice, Evolution, and Evince
  • ·Thunderbird on RHEL 8.4 and later uses the system NSS library and does not need a separate Thunderbird update; earlier RHEL 8 extended life streams require updating both Thunderbird and NSS
  • ·TLS certificate validation, X.509, OCSP, and CRL functionality in NSS-linked applications may also be impacted depending on NSS configuration — scope of exposure is broader than just S/MIME
  • ·Thunderbird fixed in version 91.3 per Mozilla advisory; ensure Thunderbird deployments are at or above this version

CVSS provenance

nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvdv2.07.5HIGHAV:N/AC:L/Au:N/C:P/I:P/A:P
osv9.8CRITICAL
vendor_debian9.8CRITICAL
vendor_msrc9.8CRITICAL
vendor_oracle9.8CRITICAL
vendor_redhat9.8CRITICAL
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