CVE-2019-14859: Ecdsa Improper Verification Of Cryptographic Signature Vulnerability

CRITICAL
Advisory Identifier: GHSA-8qxj-f9rh-9fg2
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CVSS 9.1
CWE-347
Published
Advisory Summary

CVE-2019-14859 is a CRITICAL (CVSS 9.1) improper verification of cryptographic signature vulnerability (CWE-347: Improper Verification of Cryptographic Signature) affecting Ecdsa libraries in the PyPI ecosystem. The issue involves improper verification of cryptographic signature in pure-python ecdsa. Remediation is available by upgrading affected packages to version 0.13.3.

CVE-2019-14859 at a Glance

CVE Identifier CVE-2019-14859
GHSA Identifier GHSA-8qxj-f9rh-9fg2
Severity CRITICAL
CVSS v3.1 Base Score 9.1
CWE Classification CWE-347: Improper Verification of Cryptographic Signature
Affected Product Ecdsa
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 9.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2019-14859

To remediate this vulnerability, upgrade all affected Ecdsa dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

ecdsa fixed: 0.13.3 
pip install ecdsa>=0.13.3
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show ecdsa

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2019-14859, inspect your installed packages using pip:

pip show ecdsa

Analyze the terminal output to locate any version of Ecdsa in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.13.3), your application is affected.

Note: The pip show ecdsa command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-347: Improper Verification of Cryptographic Signature, where the product does not verify, or incorrectly verifies, the cryptographic signature for data. In Ecdsa, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

A flaw was found in all python-ecdsa versions before 0.13.3, where it did not correctly verify whether signatures used DER encoding. Without this verification, a malformed signature could be accepted, making the signature malleable. Without proper verification, an attacker could use a malleable signature to create false transactions.

CVE-2019-14859 Affected Ecdsa Versions

1 component(s)
Fixed Versions:
0.13.3
Product / Package Ecosystem Affected Versions Fixed Version
ecdsa
pypi/ecdsa
PyPI
< 0.13.3
0.13.3

References

NVD — CVE-2019-14859 NVD
https://nvd.nist.gov/vuln/detail/CVE-2019-14859
Ecdsa Source Repository REPOSITORY
https://github.com/warner/python-ecdsa/issues/114
Ecdsa Source Repository REPOSITORY
https://github.com/warner/python-ecdsa/pull/115
Security Fix Commit FIX COMMIT
https://github.com/tlsfuzzer/python-ecdsa/commit/3427fa29f319b27898a28601955807abb44c0830
Security Fix Commit FIX COMMIT
https://github.com/tlsfuzzer/python-ecdsa/commit/9080d1d5ac533da0de00466aaffb49bee808bb4e
Security Fix Commit FIX COMMIT
https://github.com/tlsfuzzer/python-ecdsa/commit/b0ea52bb3aa9a16c9a4a91fdc0041edbfed10b31
bugzilla.redhat.com/show_bug.cgi WEB
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-14859
GitHub Advisory / Wiki ADVISORY
https://github.com/advisories/GHSA-8qxj-f9rh-9fg2
Ecdsa Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/ecdsa/PYSEC-2020-163.yaml
Ecdsa Source Repository REPOSITORY
https://github.com/warner/python-ecdsa
Ecdsa Release RELEASE
https://github.com/warner/python-ecdsa/releases/tag/python-ecdsa-0.13.3
pypi.org/project/ecdsa/0.13.... WEB
https://pypi.org/project/ecdsa/0.13.3

Frequently Asked Questions

What is CVE-2019-14859?
CVE-2019-14859 is a security vulnerability in Ecdsa involving Improper Verification of Cryptographic Signature in Pure-Python ECDSA under CWE-347: Improper Verification of Cryptographic Signature.
Which Ecdsa versions are affected?
Affected versions include releases prior to 0.13.3 across affected packages: ecdsa.
What version fixes CVE-2019-14859?
Upgrading to 0.13.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is ecdsa affected?
Yes, ecdsa is affected in releases prior to 0.13.3. Upgrade your dependency to 0.13.3 or later.
What is the CVSS score of CVE-2019-14859?
CVE-2019-14859 has a CVSS v3.1 base score of 9.1 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
What CWE is associated with CVE-2019-14859?
CVE-2019-14859 is classified under CWE-347: Improper Verification of Cryptographic Signature (The product does not verify, or incorrectly verifies, the cryptographic signature for data.).
How can I check PyPI dependencies for CVE-2019-14859?
Run the dependency tree command: 'pip show ecdsa'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
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  "schema_version" : "1.4.0",
  "id" : "GHSA-8qxj-f9rh-9fg2",
  "modified" : "2024-09-20T16:52:23Z",
  "published" : "2020-04-01T16:35:26Z",
  "aliases" : [ "CVE-2019-14859" ],
  "summary" : "Improper Verification of Cryptographic Signature in Pure-Python ECDSA",
  "details" : "A flaw was found in all python-ecdsa versions before 0.13.3, where it did not correctly verify whether signatures used DER encoding. Without this verification, a malformed signature could be accepted, making the signature malleable. Without proper verification, an attacker could use a malleable signature to create false transactions.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"
  } ],
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      } ]
    } ]
  } ],
  "references" : [ {
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    "type" : "WEB",
    "url" : "https://github.com/warner/python-ecdsa/issues/114"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/warner/python-ecdsa/pull/115"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/tlsfuzzer/python-ecdsa/commit/3427fa29f319b27898a28601955807abb44c0830"
  }, {
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  }, {
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  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/warner/python-ecdsa"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/warner/python-ecdsa/releases/tag/python-ecdsa-0.13.3"
  }, {
    "type" : "WEB",
    "url" : "https://pypi.org/project/ecdsa/0.13.3"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-347" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2020-04-01T15:40:54Z",
    "nvd_published_at" : "2020-01-02T15:15:00Z"
  }
}