Vulnerability identifier: #VU97633

Vulnerability risk: Low

CVSSv3.1: 3.8 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2024-5642

CWE-ID: CWE-125

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Python
Universal components / Libraries / Scripting languages

Vendor: Python.org

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to CPython 3.9 and earlier doesn't disallow configuring an empty list ("[]") for SSLContext.set_npn_protocols() which is an invalid value for the underlying OpenSSL API when NPN is used. A remote attacker can trigger an out-of-bounds read error and perform a denial of service (DoS) attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Python: 3.9.0 - 3.9.19, 3.8 - 3.8.19, 3.7 - 3.7.17

---

External links
http://jbp.io/2024/06/27/cve-2024-5535-openssl-memory-safety.html
http://github.com/python/cpython/pull/23014
http://mail.python.org/archives/list/security-announce@python.org/thread/PLP2JI3PJY33YG6P5BZYSSNU66HASXBQ/
http://github.com/python/cpython/commit/39258d3595300bc7b952854c915f63ae2d4b9c3e
http://www.openwall.com/lists/oss-security/2024/06/28/4
http://github.com/python/cpython/issues/121227
http://security.netapp.com/advisory/ntap-20240726-0005/
http://github.com/advisories/GHSA-hrvr-7x5w-xpmq

---

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.