# pyopenssl (PyPI) vulnerabilities

5 known vulnerabilities (1 high, 1 low), with the versions each affects and the releases that fix them.

## At a glance

- Latest release: not known (cve.now hasn't read this package's releases)
- Newest unaffected release: not known without release data
- Weekly downloads: 43.4M
- Dependents: 5,132
- Registry: https://pypi.org/project/pyopenssl/

## Advisories (5)

### [CVE-2026-27459](https://cve.now/CVE-2026-27459): pyOpenSSL DTLS cookie callback buffer overflow

- Severity: High 7.2
- Published: Mar 17, 2026
- Affected: from 22.0.0, fixed in 26.0.0.

### [CVE-2026-27448](https://cve.now/CVE-2026-27448): pyOpenSSL allows TLS connection bypass via unhandled callback exception in set\_tlsext\_servername\_callback

- Severity: Low 1.7
- Published: Mar 17, 2026
- Affected: from 0.14.0, fixed in 26.0.0; from 0.14, fixed in 26.0.0.

### [CVE-2018-1000808](https://cve.now/CVE-2018-1000808): Python Cryptographic Authority pyopenssl version Before 17.5.0 contains a CWE - 401 : Failure to Release Memory Before Removing Last…

- Severity: Unrated
- Published: Oct 8, 2018
- Affected: fixed in 17.5.0.

### [CVE-2018-1000807](https://cve.now/CVE-2018-1000807): Python Cryptographic Authority pyopenssl version prior to version 17.5.0 contains a CWE-416: Use After Free vulnerability in X509 object…

- Severity: Unrated
- Published: Oct 8, 2018
- Affected: fixed in 17.5.0.

### [CVE-2013-4314](https://cve.now/CVE-2013-4314): The X509Extension in pyOpenSSL before 0.13.1 does not properly handle a '\\0' character in a domain name in the Subject Alternative Name…

- Severity: Unrated
- Published: Sep 30, 2013
- Affected: fixed in 0.13.1.

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