CVE-2026-26007: Cryptography Cryptography Vulnerable To A Subgroup Vulnerability

HIGH
Advisory Identifier: GHSA-r6ph-v2qm-q3c2
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CWE-345
Published
Advisory Summary

CVE-2026-26007 is a HIGH cryptography vulnerable to a subgroup vulnerability (CWE-345: Insufficient Verification of Data Authenticity) affecting Cryptography libraries in the PyPI ecosystem. The issue involves cryptography vulnerable to a subgroup attack due to missing subgroup validation for sect curves. Remediation is available by upgrading affected packages to version 46.0.5.

CVE-2026-26007 at a Glance

CVE Identifier CVE-2026-26007
GHSA Identifier GHSA-r6ph-v2qm-q3c2
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-345: Insufficient Verification of Data Authenticity
Affected Product Cryptography
Package Ecosystem PyPI
Published Date
Last Updated

How to Fix CVE-2026-26007

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

cryptography fixed: 46.0.5 
pip install cryptography>=46.0.5
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 cryptography

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-26007, inspect your installed packages using pip:

pip show cryptography

Analyze the terminal output to locate any version of Cryptography in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 46.0.5), your application is affected.

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

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-345: Insufficient Verification of Data Authenticity, where the product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data. In Cryptography, 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

## Vulnerability Summary The `public_key_from_numbers` (or `EllipticCurvePublicNumbers.public_key()`), `EllipticCurvePublicNumbers.public_key()`, `load_der_public_key()` and `load_pem_public_key()` functions do not verify that the point belongs to the expected prime-order subgroup of the curve. This missing validation allows an attacker to provide a public key point `P` from a small-order subgroup. This can lead to security issues in various situations, such as the most commonly used signature verification (ECDSA) and shared key negotiation (ECDH). When the victim computes the shared secret as `S = [victim_private_key]P` via ECDH, this leaks information about `victim_private_key mod (small_subgroup_order)`. For curves with cofactor > 1, this reveals the least significant bits of the private key. When these weak public keys are used in ECDSA , it's easy to forge signatures on the small subgroup. Only SECT curves are impacted by this. ## Credit This vulnerability was discovered by: - XlabAI Team of Tencent Xuanwu Lab - Atuin Automated Vulnerability Discovery Engine

CVE-2026-26007 Affected Cryptography Versions

1 component(s)
Fixed Versions:
46.0.5
Product / Package Ecosystem Affected Versions Fixed Version
cryptography
pypi/cryptography
PyPI
< 46.0.5
46.0.5

References

GitHub Advisory / Wiki ADVISORY
https://github.com/pyca/cryptography/security/advisories/GHSA-r6ph-v2qm-q3c2
NVD — CVE-2026-26007 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-26007
Security Fix Commit FIX COMMIT
https://github.com/pyca/cryptography/commit/0eebb9dbb6343d9bc1d91e5a2482ed4e054a6d8c
Cryptography Source Repository REPOSITORY
https://github.com/pyca/cryptography
Cryptography Release RELEASE
https://github.com/pyca/cryptography/releases/tag/46.0.5
Cryptography Security Information SECURITY
http://www.openwall.com/lists/oss-security/2026/02/10/4

Frequently Asked Questions

What is CVE-2026-26007?
CVE-2026-26007 is a security vulnerability in Cryptography involving cryptography Vulnerable to a Subgroup Attack Due to Missing Subgroup Validation for SECT Curves under CWE-345: Insufficient Verification of Data Authenticity.
Which Cryptography versions are affected?
Affected versions include releases prior to 46.0.5 across affected packages: cryptography.
What version fixes CVE-2026-26007?
Upgrading to 46.0.5 (or the latest patched release for your respective branch) resolves the vulnerability.
Is cryptography affected?
Yes, cryptography is affected in releases prior to 46.0.5. Upgrade your dependency to 46.0.5 or later.
What CWE is associated with CVE-2026-26007?
CVE-2026-26007 is classified under CWE-345: Insufficient Verification of Data Authenticity (The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.).
How can I check PyPI dependencies for CVE-2026-26007?
Run the dependency tree command: 'pip show cryptography'. 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 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-r6ph-v2qm-q3c2",
  "modified" : "2026-02-11T14:14:19Z",
  "published" : "2026-02-10T21:27:06Z",
  "aliases" : [ "CVE-2026-26007" ],
  "summary" : "cryptography Vulnerable to a Subgroup Attack Due to Missing Subgroup Validation for SECT Curves",
  "details" : "## Vulnerability Summary\n\nThe `public_key_from_numbers` (or `EllipticCurvePublicNumbers.public_key()`), `EllipticCurvePublicNumbers.public_key()`, `load_der_public_key()` and `load_pem_public_key()` functions do not verify that the point belongs to the expected prime-order subgroup of the curve.\n\nThis missing validation allows an attacker to provide a public key point `P` from a small-order subgroup.  This can lead to security issues in various situations, such as the most commonly used signature verification (ECDSA) and shared key negotiation (ECDH). When the victim computes the shared secret as `S = [victim_private_key]P` via ECDH,  this leaks information about `victim_private_key mod (small_subgroup_order)`. For curves with cofactor > 1, this reveals the least significant bits of the private key.  When these weak public keys are used in ECDSA , it's easy to forge signatures on the small subgroup.\n\nOnly SECT curves are impacted by this.\n\n## Credit\n\nThis vulnerability was discovered by:\n- XlabAI Team of Tencent Xuanwu Lab\n- Atuin Automated Vulnerability Discovery Engine",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "cryptography"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "46.0.5"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 46.0.4"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/pyca/cryptography/security/advisories/GHSA-r6ph-v2qm-q3c2"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-26007"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pyca/cryptography/commit/0eebb9dbb6343d9bc1d91e5a2482ed4e054a6d8c"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/pyca/cryptography"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pyca/cryptography/releases/tag/46.0.5"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2026/02/10/4"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-345" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-02-10T21:27:06Z",
    "nvd_published_at" : "2026-02-10T22:17:00Z"
  }
}