cryptography NULL pointer dereference with pkcs12.serialize_key_and_certificates when called with a non-matching certificate and private key and an hmac_hash override

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2024-26130: 0.83% estimated exploitation activity in the next 30 days; percentile 57.62 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

If pkcs12.serializekeyandcertificates is called with both: 1. A certificate whose public key did not match the provided private key 2. An encryptionalgorithm with hmachash set (via PrivateFormat.PKCS12.encryptionbuilder().hmachash(...) Then a NULL pointer dereference would occur, crashing the Python process. This has been resolved, and now a ValueError is properly raised. Patched in https://github.com/pyca/cryptography/pull/10423

Published by the source

21 Feb 2024, 18:04 UTC

Last modified by the source

10 Sep 2026, 03:50 UTC

Source last checked

26 Oct 2026, 13:37 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-6vqw-3v5j-54x4

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-6vqw-3v5j-54x4

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# Patch Next advisory brief: CVE-2024-26130

Advisory: cryptography NULL pointer dereference with pkcs12.serialize_key_and_certificates when called with a non-matching certificate and private key and an hmac_hash override
IDs: CVE-2024-26130, GHSA-6vqw-3v5j-54x4
Record: https://patchnext.com/advisories/cve-2024-26130 (revision 2, source checked 26 Oct 2026, 13:37 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: cryptography 42.0.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI cryptography: affected >= 38.0.0, < 42.0.4; fixed in 42.0.4

## Suggested inspection (read-only)
- `python -m pip show cryptography`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on cryptography.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-6vqw-3v5j-54x4 (OSV record GHSA-6vqw-3v5j-54x4 lists affected ranges: PyPI cryptography >=38.0.0 <42.0.4 (fixed))
- Verified: https://github.com/advisories/GHSA-6vqw-3v5j-54x4 (GitHub-reviewed advisory GHSA-6vqw-3v5j-54x4 lists affected ranges: PyPI cryptography >=38.0.0 <42.0.4)

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