# CVE-2021-20305: libhogweed6t64: A flaw was found in Nettle in versions before 3.7.2, where several Nettlesignature verification functions (GOST DSA,... CVE-2021-20305 is fixed in 14 products on 1 platform, first by libhogweed4 3.4-1ubuntu0.1, released April 5, 2021. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2021-20305 - Priority: High - CVSS: 8.1 (Medium) - EPSS: 0.0167 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Apr 5, 2021 ## Description A flaw was found in Nettle in versions before 3.7.2, where several Nettlesignature verification functions (GOST DSA, EDDSA & ECDSA) result in theElliptic Curve Cryptography point (ECC) multiply function being called without-of-range scalers, possibly resulting in incorrect results. This flawallows an attacker to force an invalid signature, causing an assertionfailure or possible validation. The highest threat to this vulnerability isto confidentiality, integrity, as well as system availability. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | gnutls RHEL 8 | 0:3.6.14-8.el8_3 | [RHSA-2021:1206](https://patchblox.com/security/data/fix/linux/rhsa-2021-1206.md) | Apr 14, 2021 | | Linux | gnutls ol 8 | 0:3.6.14-8.el8_3 | [ELSA-2021-1206](https://patchblox.com/security/data/fix/linux/elsa-2021-1206.md) | Apr 16, 2021 | | Linux | gnutls-c++ RHEL 8 | 0:3.6.14-8.el8_3 | [RHSA-2021:1206](https://patchblox.com/security/data/fix/linux/rhsa-2021-1206.md) | Apr 14, 2021 | | Linux | gnutls-c++ ol 8 | 0:3.6.14-8.el8_3 | [ELSA-2021-1206](https://patchblox.com/security/data/fix/linux/elsa-2021-1206.md) | Apr 16, 2021 | | Linux | gnutls-dane RHEL 8 | 0:3.6.14-8.el8_3 | [RHSA-2021:1206](https://patchblox.com/security/data/fix/linux/rhsa-2021-1206.md) | Apr 14, 2021 | | Linux | gnutls-dane ol 8 | 0:3.6.14-8.el8_3 | [ELSA-2021-1206](https://patchblox.com/security/data/fix/linux/elsa-2021-1206.md) | Apr 16, 2021 | | Linux | gnutls-devel RHEL 8 | 0:3.6.14-8.el8_3 | [RHSA-2021:1206](https://patchblox.com/security/data/fix/linux/rhsa-2021-1206.md) | Apr 14, 2021 | | Linux | gnutls-devel ol 8 | 0:3.6.14-8.el8_3 | [ELSA-2021-1206](https://patchblox.com/security/data/fix/linux/elsa-2021-1206.md) | Apr 16, 2021 | | Linux | gnutls-utils RHEL 8 | 0:3.6.14-8.el8_3 | [RHSA-2021:1206](https://patchblox.com/security/data/fix/linux/rhsa-2021-1206.md) | Apr 14, 2021 | | Linux | gnutls-utils ol 8 | 0:3.6.14-8.el8_3 | [ELSA-2021-1206](https://patchblox.com/security/data/fix/linux/elsa-2021-1206.md) | Apr 16, 2021 | | Linux | libhogweed4 Ubuntu 18.04.6 LTS (bionic) | 3.4-1ubuntu0.1 | [libhogweed4 3.4-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libhogweed4-3.4-1ubuntu0.1.md) | Apr 5, 2021 | | Linux | libhogweed5 Ubuntu 20.04 LTS (focal) | 3.5.1+really3.5.1-2ubuntu0.1 | [libhogweed5 3.5.1+really3.5.1-2ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libhogweed5-3.5.1-really3.5.1-2ubuntu0.1.md) | Apr 5, 2021 | | Linux | libhogweed6t64 Ubuntu 24.10 (oracular) | 3.7-2.1ubuntu1 | [libhogweed6t64 3.7-2.1ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-libhogweed6t64-3.7-2.1ubuntu1.md) | Jan 16, 2026 | | Linux | libhogweed6t64 Ubuntu 25.04 (plucky) | 3.7-2.1ubuntu1 | [libhogweed6t64 3.7-2.1ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-libhogweed6t64-3.7-2.1ubuntu1.md) | Jan 16, 2026 | | Linux | libnettle6 Ubuntu 18.04.6 LTS (bionic) | 3.4-1ubuntu0.1 | [libnettle6 3.4-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libnettle6-3.4-1ubuntu0.1.md) | Apr 5, 2021 | | Linux | libnettle7 Ubuntu 20.04 LTS (focal) | 3.5.1+really3.5.1-2ubuntu0.1 | [libnettle7 3.5.1+really3.5.1-2ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libnettle7-3.5.1-really3.5.1-2ubuntu0.1.md) | Apr 5, 2021 | | Linux | libnettle8t64 Ubuntu 24.10 (oracular) | 3.7-2.1ubuntu1 | [libnettle8t64 3.7-2.1ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-libnettle8t64-3.7-2.1ubuntu1.md) | Jan 16, 2026 | | Linux | libnettle8t64 Ubuntu 25.04 (plucky) | 3.7-2.1ubuntu1 | [libnettle8t64 3.7-2.1ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-libnettle8t64-3.7-2.1ubuntu1.md) | Jan 16, 2026 | | Linux | nettle RHEL 8 | 0:3.4.1-4.el8_3 | [RHSA-2021:1206](https://patchblox.com/security/data/fix/linux/rhsa-2021-1206.md) | Apr 14, 2021 | | Linux | nettle ol 8 | 0:3.4.1-4.el8_3 | [ELSA-2021-1206](https://patchblox.com/security/data/fix/linux/elsa-2021-1206.md) | Apr 16, 2021 | | Linux | nettle-bin Ubuntu 18.04.6 LTS (bionic) | 3.4-1ubuntu0.1 | [nettle-bin 3.4-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-nettle-bin-3.4-1ubuntu0.1.md) | Apr 5, 2021 | | Linux | nettle-bin Ubuntu 20.04 LTS (focal) | 3.5.1+really3.5.1-2ubuntu0.1 | [nettle-bin 3.5.1+really3.5.1-2ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-nettle-bin-3.5.1-really3.5.1-2ubuntu0.1.md) | Apr 5, 2021 | | Linux | nettle-bin Ubuntu 24.10 (oracular) | 3.7-2.1ubuntu1 | [nettle-bin 3.7-2.1ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-nettle-bin-3.7-2.1ubuntu1.md) | Jan 16, 2026 | | Linux | nettle-bin Ubuntu 25.04 (plucky) | 3.7-2.1ubuntu1 | [nettle-bin 3.7-2.1ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-nettle-bin-3.7-2.1ubuntu1.md) | Jan 16, 2026 | | Linux | nettle-devel RHEL 8 | 0:3.4.1-4.el8_3 | [RHSA-2021:1206](https://patchblox.com/security/data/fix/linux/rhsa-2021-1206.md) | Apr 14, 2021 | | Linux | nettle-devel ol 8 | 0:3.4.1-4.el8_3 | [ELSA-2021-1206](https://patchblox.com/security/data/fix/linux/elsa-2021-1206.md) | Apr 16, 2021 | --- Data as of 2026-11-09T07:25:28Z UTC. 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