{"id":"CVE-2021-33560","title":"Libgcrypt before 1.8.8 and 1.9.x before 1.9.3 mishandles ElGamal encryption because it lacks exponent blinding to address a side-channel attack against mpi_powm, and the window size is not chosen appropriately","summary":"Libgcrypt before 1.8.8 and 1.9.x before 1.9.3 mishandles ElGamal encryption because it lacks exponent blinding to address a side-channel attack against mpi_powm, and the window size is not chosen appropriately. This, for example, affects…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","cwe":["CWE-203","CWE-325"],"vendor":"gnupg","product":"libgcrypt","affected":["libgcrypt < 1.8.8","libgcrypt >= 1.9.0, < 1.9.3","debian_linux = 9.0","fedora = 33","fedora = 34","communications_cloud_native_core_binding_support_function = 1.11.0","communications_cloud_native_core_network_function_cloud_native_environment = 1.9.0","communications_cloud_native_core_network_function_cloud_native_environment = 1.10.0","communications_cloud_native_core_network_repository_function = 1.14.0","communications_cloud_native_core_network_repository_function = 1.15.0","communications_cloud_native_core_network_repository_function = 1.15.1","communications_cloud_native_core_network_slice_selection_function = 1.8.0","communications_cloud_native_core_service_communication_proxy = 1.15.0"],"patched":["libgcrypt 1.9.3"],"published":"2021-06-08","updated":"2026-10-14","sourceUpdated":"2026-10-14T12:17:12.267","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2021-33560","references":[{"url":"https://dev.gnupg.org/T5305","label":"cve@mitre.org"},{"url":"https://dev.gnupg.org/T5328","label":"cve@mitre.org"},{"url":"https://dev.gnupg.org/T5466","label":"cve@mitre.org"},{"url":"https://dev.gnupg.org/rCe8b7f10be275bcedb5fc05ed4837a89bfd605c61","label":"cve@mitre.org"},{"url":"https://lists.debian.org/debian-lts-announce/2021/06/msg00021.html","label":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BKKTOIGFW2SGN3DO2UHHVZ7MJSYN4AAB/","label":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/R7OAPCUGPF3VLA7QAJUQSL255D4ITVTL/","label":"cve@mitre.org"},{"url":"https://security.gentoo.org/glsa/202210-13","label":"cve@mitre.org"},{"url":"https://www.oracle.com/security-alerts/cpuapr2022.html","label":"cve@mitre.org"},{"url":"https://www.oracle.com/security-alerts/cpujan2022.html","label":"cve@mitre.org"},{"url":"https://www.oracle.com/security-alerts/cpujul2022.html","label":"cve@mitre.org"},{"url":"https://www.oracle.com/security-alerts/cpuoct2021.html","label":"cve@mitre.org"},{"url":"https://dev.gnupg.org/T5305","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://dev.gnupg.org/T5328","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://dev.gnupg.org/T5466","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://dev.gnupg.org/rCe8b7f10be275bcedb5fc05ed4837a89bfd605c61","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2021/06/msg00021.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BKKTOIGFW2SGN3DO2UHHVZ7MJSYN4AAB/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/R7OAPCUGPF3VLA7QAJUQSL255D4ITVTL/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/202210-13","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpuapr2022.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpujan2022.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpujul2022.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpuoct2021.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-398330.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","exploit-available","cve.org"],"epss":0.02342,"epssPercentile":0.83198,"exploits":{"github":1,"githubRepos":["https://github.com/IBM/PGP-client-checker-CVE-2021-33560"],"checkedAt":"2026-10-14T12:29:44.470Z"},"exploitAvailable":true,"ingestedAt":"2026-10-14T12:29:10.819Z","ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2025-12-03T14:39:05.498424Z"},"slug":"CVE-2021-33560","body":"## Overview\n\nLibgcrypt before 1.8.8 and 1.9.x before 1.9.3 mishandles ElGamal encryption because it lacks exponent blinding to address a side-channel attack against mpi_powm, and the window size is not chosen appropriately. This, for example, affects use of ElGamal in OpenPGP.\n\n## Affected\n\n- `libgcrypt < 1.8.8`\n- `libgcrypt >= 1.9.0, < 1.9.3`\n- `debian_linux = 9.0`\n- `fedora = 33`\n- `fedora = 34`\n- `communications_cloud_native_core_binding_support_function = 1.11.0`\n- `communications_cloud_native_core_network_function_cloud_native_environment = 1.9.0`\n- `communications_cloud_native_core_network_function_cloud_native_environment = 1.10.0`\n- `communications_cloud_native_core_network_repository_function = 1.14.0`\n- `communications_cloud_native_core_network_repository_function = 1.15.0`\n- `communications_cloud_native_core_network_repository_function = 1.15.1`\n- `communications_cloud_native_core_network_slice_selection_function = 1.8.0`\n- `communications_cloud_native_core_service_communication_proxy = 1.15.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `libgcrypt 1.9.3`","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":41.3,"likelihood":0.5,"exploitation":12,"ransomware":0},"changes":[]}