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CryptographyApplication · Cryptography.io

CVE-2026-39892

CRITICAL · 9.8 CVSS v3.1 Published 2026-04-08
Fix available
A fix is available. Upgrade to 46.0.7 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. From 45.0.0 to before 46.0.7, if a non-contiguous buffer was passed to APIs which accepted Python buffers (e.g. Hash.update()), this could lead to buffer overflows. This vulnerability is fixed in 46.0.7.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Buffer overflow vulnerability in Python cryptography library versions 45.0.0-46.0.6 where non-contiguous buffers (e.g., memoryviews, slices) passed to APIs accepting Python buffers such as Hash.update() are not properly validated, allowing memory corruption and potential remote code execution.

MitigationUpgrade cryptography package to version 46.0.7 or later to patch the buffer overflow; ensure thorough testing of all cryptographic operations after upgrade due to critical severity.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
CryptographyApplication
Affected:>= 45.0.0, < 46.0.7

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check if cryptography package is installed
    Run 'pip show cryptography' or 'python -c "import cryptography; print(cryptography.__version__)"'
    Affected if The package is not installed or cannot be imported
  2. Verify installed version against affected range
    Compare the output from step 1 to the affected versions: 45.0.0 through 46.0.6 inclusive
    Affected if Installed version is >= 45.0.0 and < 46.0.7
  3. Identify use of vulnerable buffer APIs
    Search codebase for calls to Hash.update() or similar Python buffer-accepting APIs that process external input
    Affected if Code passes non-contiguous memory buffers (e.g., numpy arrays, memoryviews, bytearrays) to Hash.update() or similar cryptographic APIs

User is affected if cryptography version is 45.0.0 through 46.0.6 AND code passes non-contiguous buffers to Hash.update() or similar APIs.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 46.0.7 or later
Fixed in 46.0.7
Interim mitigation

Upgrade cryptography package to version 46.0.7 or later to patch the buffer overflow; ensure thorough testing of all cryptographic operations after upgrade due to critical severity.

Recommended fix High confidence

46.0.7

  1. Check the currently installed cryptography package version: pip show cryptography
  2. Upgrade the cryptography package to version 46.0.7: pip install --upgrade cryptography==46.0.7
  3. Verify the upgrade was successful: pip show cryptography
  4. Run application tests to ensure compatibility with the new version
  5. If using a requirements file, update the cryptography version specification to cryptography>=46.0.7
Caveat The official description does not mention breaking changes; however, review the cryptography project changelog between 45.0.0 and 46.0.7 for any potentially breaking changes in your usage

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Cryptography Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing3.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,010
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-39892 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
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