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CVE-2021-43572

30
FAUCET Score

CVE-2021-43572 is a critical vulnerability affecting the Stark Bank Python ECDSA library (starkbank-ecdsa or ecdsa-python) before version 2.0.1. The flaw allows attackers to forge digital signatures on arbitrary messages due to the verify function failing to check for non-zero signatures. With a CVSS score of 9.8 (CRITICAL), this vulnerability is remotely exploitable with low attack complexity, potentially leading to complete compromise of confidentiality, integrity, and availability. There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 2.0.1CPE matchmatch criteria
cpe:2.3:a:starkbank:ecdsa-python:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.20%
Probability of exploitation in next 30 days
EPSS Percentile
64.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0120 is in the 51st percentile among its peer group of 36,862 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
pippatch availablevia ghsa
Product: starkbank-ecdsaFixed in: 2.0.1

Vendor Advisories (1)

pipGHSA-92vm-mxjf-jqf3critical

Improper Verification of Cryptographic Signature in starkbank-ecdsa

Nov 10, 2021

References

github.com / starkbank/ecdsa-python/commit/d136170666e9510eb63c2572551805807bd4c17f
PatchThird Party Advisory
github.com / starkbank/ecdsa-python/releases/tag/v2.0.1
Release NotesThird Party Advisory
research.nccgroup.com / 2021/11/08/technical-advisory-arbitrary-signature-forgery-in-stark-bank-ecdsa-libraries
ExploitThird Party Advisory