GitHub Advisoryadvisory · PyPI
GHSA-p423-j2cm-9vmq Cryptography vulnerable to buffer overflow if non-contiguous buffers were passed to APIs
MEDIUM
Official page ↗
- Aliases
- CVE-2026-39892
- Ecosystem
- PyPI
- Packages
- cryptography
- Severity
- Moderate
- CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
- Weaknesses
- CWE-119
- Reviewed
- 2026-04-08
Affected packages
• PyPI cryptography: >= 45.0.0, < 46.0.7 → fixed in 46.0.7
Description
If a non-contiguous buffer was passed to APIs which accepted Python buffers (e.g. `Hash.update()`), this could lead to buffer overflows. For example:
```python
h = Hash(SHA256())
b.update(buf[::-1])
```
would read past the end of the buffer on Python >3.11
Related
Alias · CVE (1)
- CVE-2026-39892 cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. vulnerability
Weakness · CWE (1)
- CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer weakness
References
- https://github.com/pyca/cryptography/security/advisories/GHSA-p423-j2cm-9vmq web
- https://nvd.nist.gov/vuln/detail/CVE-2026-39892 advisory
- https://github.com/pyca/cryptography package
- https://github.com/pypa/advisory-database/tree/main/vulns/cryptography/PYSEC-2026-36.yaml web
- http://www.openwall.com/lists/oss-security/2026/04/08/12 web