{"id":"UBUNTU-CVE-2023-4421","details":"The NSS code used for checking PKCS#1 v1.5 was leaking information useful in mounting Bleichenbacher-like attacks. Both the overall correctness of the padding as well as the length of the encrypted message was leaking through timing side-channel. By sending large number of attacker-selected ciphertexts, the attacker would be able to decrypt a previously intercepted PKCS#1 v1.5 ciphertext (for example, to decrypt a TLS session that used RSA key exchange), or forge a signature using the victim's key. The issue was fixed by implementing the implicit rejection algorithm, in which the NSS returns a deterministic random message in case invalid padding is detected, as proposed in the Marvin Attack paper. This vulnerability affects NSS \u003c 3.61.","modified":"2026-04-22T16:53:37.435109Z","published":"2023-12-12T17:15:00Z","related":["USN-6727-1"],"upstream":["CVE-2023-4421"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2023-4421"},{"type":"REPORT","url":"https://access.redhat.com/security/cve/CVE-2023-4421"},{"type":"REPORT","url":"https://people.redhat.com/~hkario/marvin/"},{"type":"REPORT","url":"https://www.mozilla.org/en-US/security/advisories/mfsa2023-53/"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-6727-1"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2023-4421"}],"affected":[{"package":{"name":"nss","ecosystem":"Ubuntu:Pro:14.04:LTS","purl":"pkg:deb/ubuntu/nss@2:3.28.4-0ubuntu0.14.04.5+esm13?arch=source&distro=esm-infra-legacy/trusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2:3.15.1-1ubuntu1","2:3.15.2-1","2:3.15.3-1","2:3.15.3.1-1","2:3.15.3.1-1.1","2:3.15.3.1-1.1ubuntu1","2:3.15.4-1ubuntu3","2:3.15.4-1ubuntu4","2:3.15.4-1ubuntu5","2:3.15.4-1ubuntu6","2:3.15.4-1ubuntu7","2:3.15.4-1ubuntu7.1","2:3.17-0ubuntu0.14.04.1","2:3.17.1-0ubuntu0.14.04.1","2:3.17.1-0ubuntu0.14.04.2","2:3.17.4-0ubuntu0.14.04.1","2:3.19.2-0ubuntu0.14.04.1","2:3.19.2.1-0ubuntu0.14.04.1","2:3.19.2.1-0ubuntu0.14.04.2","2:3.21-0ubuntu0.14.04.1","2:3.21-0ubuntu0.14.04.2","2:3.23-0ubuntu0.14.04.1","2:3.26.2-0ubuntu0.14.04.3","2:3.28.4-0ubuntu0.14.04.1","2:3.28.4-0ubuntu0.14.04.2","2:3.28.4-0ubuntu0.14.04.3","2:3.28.4-0ubuntu0.14.04.4","2:3.28.4-0ubuntu0.14.04.5","2:3.28.4-0ubuntu0.14.04.5+esm1","2:3.28.4-0ubuntu0.14.04.5+esm2","2:3.28.4-0ubuntu0.14.04.5+esm3","2:3.28.4-0ubuntu0.14.04.5+esm4","2:3.28.4-0ubuntu0.14.04.5+esm5","2:3.28.4-0ubuntu0.14.04.5+esm6","2:3.28.4-0ubuntu0.14.04.5+esm7","2:3.28.4-0ubuntu0.14.04.5+esm8","2:3.28.4-0ubuntu0.14.04.5+esm9","2:3.28.4-0ubuntu0.14.04.5+esm10","2:3.28.4-0ubuntu0.14.04.5+esm11","2:3.28.4-0ubuntu0.14.04.5+esm12","2:3.28.4-0ubuntu0.14.04.5+esm13"],"ecosystem_specific":{"binaries":[{"binary_name":"libnss3","binary_version":"2:3.28.4-0ubuntu0.14.04.5+esm13"},{"binary_name":"libnss3-1d","binary_version":"2:3.28.4-0ubuntu0.14.04.5+esm13"},{"binary_name":"libnss3-nssdb","binary_version":"2:3.28.4-0ubuntu0.14.04.5+esm13"},{"binary_name":"libnss3-tools","binary_version":"2:3.28.4-0ubuntu0.14.04.5+esm13"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2023/UBUNTU-CVE-2023-4421.json"}},{"package":{"name":"nss","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/nss@2:3.28.4-0ubuntu0.16.04.14+esm5?arch=source&distro=esm-infra/xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2:3.19.2-1ubuntu1","2:3.19.2.1-0ubuntu1","2:3.21-1ubuntu2","2:3.21-1ubuntu3","2:3.21-1ubuntu4","2:3.23-0ubuntu0.16.04.1","2:3.26.2-0ubuntu0.16.04.2","2:3.28.4-0ubuntu0.16.04.1","2:3.28.4-0ubuntu0.16.04.2","2:3.28.4-0ubuntu0.16.04.3","2:3.28.4-0ubuntu0.16.04.4","2:3.28.4-0ubuntu0.16.04.5","2:3.28.4-0ubuntu0.16.04.6","2:3.28.4-0ubuntu0.16.04.8","2:3.28.4-0ubuntu0.16.04.9","2:3.28.4-0ubuntu0.16.04.10","2:3.28.4-0ubuntu0.16.04.11","2:3.28.4-0ubuntu0.16.04.12","2:3.28.4-0ubuntu0.16.04.13","2:3.28.4-0ubuntu0.16.04.14","2:3.28.4-0ubuntu0.16.04.14+esm1","2:3.28.4-0ubuntu0.16.04.14+esm2","2:3.28.4-0ubuntu0.16.04.14+esm3","2:3.28.4-0ubuntu0.16.04.14+esm4","2:3.28.4-0ubuntu0.16.04.14+esm5"],"ecosystem_specific":{"binaries":[{"binary_name":"libnss3","binary_version":"2:3.28.4-0ubuntu0.16.04.14+esm5"},{"binary_name":"libnss3-1d","binary_version":"2:3.28.4-0ubuntu0.16.04.14+esm5"},{"binary_name":"libnss3-nssdb","binary_version":"2:3.28.4-0ubuntu0.16.04.14+esm5"},{"binary_name":"libnss3-tools","binary_version":"2:3.28.4-0ubuntu0.16.04.14+esm5"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2023/UBUNTU-CVE-2023-4421.json"}},{"package":{"name":"nss","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/nss@2:3.35-2ubuntu2.16+esm1?arch=source&distro=esm-infra/bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2:3.32-1ubuntu3","2:3.34-1ubuntu1","2:3.35-2ubuntu2","2:3.35-2ubuntu2.1","2:3.35-2ubuntu2.2","2:3.35-2ubuntu2.3","2:3.35-2ubuntu2.5","2:3.35-2ubuntu2.6","2:3.35-2ubuntu2.7","2:3.35-2ubuntu2.8","2:3.35-2ubuntu2.9","2:3.35-2ubuntu2.11","2:3.35-2ubuntu2.12","2:3.35-2ubuntu2.13","2:3.35-2ubuntu2.14","2:3.35-2ubuntu2.15","2:3.35-2ubuntu2.16","2:3.35-2ubuntu2.16+esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"libnss3","binary_version":"2:3.35-2ubuntu2.16+esm1"},{"binary_name":"libnss3-tools","binary_version":"2:3.35-2ubuntu2.16+esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2023/UBUNTU-CVE-2023-4421.json"}},{"package":{"name":"nss","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/nss@2:3.98-0ubuntu0.20.04.1?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2:3.98-0ubuntu0.20.04.1"}]}],"versions":["2:3.45-1ubuntu2","2:3.47-1ubuntu1","2:3.47-1ubuntu2","2:3.48-1ubuntu1","2:3.49.1-1ubuntu1","2:3.49.1-1ubuntu1.1","2:3.49.1-1ubuntu1.2","2:3.49.1-1ubuntu1.4","2:3.49.1-1ubuntu1.5","2:3.49.1-1ubuntu1.6","2:3.49.1-1ubuntu1.7","2:3.49.1-1ubuntu1.8","2:3.49.1-1ubuntu1.9"],"ecosystem_specific":{"availability":"No 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