CVE-2021-20305A 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 fun…
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It affects Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP and 8 other products. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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 function being called with out-of-range scalers, possibly resulting in incorrect results. This flaw allows an attacker to force an invalid signature, causing an assertion failure or possible validation. The highest threat to this vulnerability is to confidentiality, integrity, as well as system availability.
- CVSS
- 8.1 HIGH (v3.1, NVD)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-327
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- redhat
- NVD analysis
- Modified
- Record last updated
- Oct 14, 2026
- First seen by InfoSec Signals
- Oct 14, 2026
Affected products
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.0 before V3.1.5 | CISA ADP |
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name) | from V3.1.0 before V3.1.5 | CISA ADP |
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.0 before V3.1.5 | CISA ADP |
nettle_project nettle nettle_project:nettle | before 3.7.2 | NVD |
fedoraproject fedora fedoraproject:fedora | 33 | NVD |
redhat enterprise_linux redhat:enterprise_linux | 7.0; 8.0 | NVD |
netapp active_iq_unified_manager netapp:active_iq_unified_manager | all versions | NVD |
netapp ontap_select_deploy_administration_utility netapp:ontap_select_deploy_administration_utility | all versions | NVD |
debian debian_linux debian:debian_linux | 9.0; 10.0 | NVD |
References
- https://bugzilla.redhat.com/show_bug.cgi?id=1942533x-refsource-misc, issue-tracking, patch, third-party-advisory
- https://security.gentoo.org/glsa/202105-31vendor-advisory, x-refsource-gentoo, third-party-advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MQKWVVMAIDAJ7YAA3VVO32BHLDOH2E63/vendor-advisory, x-refsource-fedora
- https://www.debian.org/security/2021/dsa-4933vendor-advisory, x-refsource-debian, third-party-advisory
- https://lists.debian.org/debian-lts-announce/2021/09/msg00008.htmlmailing-list, x-refsource-mlist, third-party-advisory
- https://security.netapp.com/advisory/ntap-20211022-0002/x-refsource-confirm, third-party-advisory
- https://cert-portal.siemens.com/productcert/html/ssa-398330.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.