CVE-2021-20305
A flaw was found in Nettle in versions before 3.7.2, where several Nettle signature verification functions (GOST DSA, EDDSA & ECDSA) result in the Elliptic Curve Cryptography point (ECC) multiply
02 Description
A flaw was found in Nettle in versions before 3.7.2, where several Nettle signature verification functions (GOST DSA, EDDSA & ECDSA) result in the Elliptic Curve Cryptography point (ECC) multiply
03 Exploitation and scoring
- Exploitation
- Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
- SSVC decision
- Not assessed by CISA
- EPSS probability
- 1.74% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 77.3% of scored records. A rank, not a probability.
- NVD base score
- 8.1 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- NVD analysis status
- Modified. NVD last modified this record on 2026-10-14.
- Red Hat severity
- Important. Red Hat's rating for its own products, not a CVSS rating.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2021-04-05 21:31Z5 YR AGO
- Last updated
- 2026-10-14 10:04Z15 DAYS AGO
- Reserved
- 2020-12-17
- Assigning CNA
- redhat
- Record state
- PUBLISHED
- Severity
- Not rated by the issuing CNA
- CNA CVSS vector
- Not published by the issuing CNA
- Weaknesses
- Data version
- 5.2
- Document digest
- 355c3c4171ec26eb767f04d4d16b25b25d968af22c157a09805257c61463dd62
05 Affected products
06 References
- bugzilla.redhat.comhttps://bugzilla.redhat.com/show_bug.cgi?id=1942533
- security.gentoo.orgGLSA-202105-31https://security.gentoo.org/glsa/202105-31
- lists.fedoraproject.orgFEDORA-2021-454a0f6f76https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MQKWVVMAIDAJ7YAA3VVO32BHLDOH2E63/
- www.debian.orgDSA-4933https://www.debian.org/security/2021/dsa-4933
- lists.debian.org[debian-lts-announce] 20210918 [SECURITY] [DLA 2760-1] nettle security updatehttps://lists.debian.org/debian-lts-announce/2021/09/msg00008.html
- security.netapp.comhttps://security.netapp.com/advisory/ntap-20211022-0002/
- cert-portal.siemens.comhttps://cert-portal.siemens.com/productcert/html/ssa-398330.html
07 Fixed in
Arch Linux
- nettle Fixed in 3.7.2-1
Source: Arch Linux Security Tracker, the Arch Linux security team. Reformatted by exploit.cc.
Debian 12
- nettle Fixed in 3.7.2-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 13
- nettle Fixed in 3.7.2-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 14
- nettle Fixed in 3.7.2-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 14.04 LTS
- nettle No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 16.04 LTS
- nettle Fixed in 3.2-1ubuntu0.16.04.2
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 18.04 LTS
- nettle Fixed in 3.4-1ubuntu0.1
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 20.04 LTS
- nettle Fixed in 3.5.1+really3.5.1-2ubuntu0.1
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.