#VU97633 Out-of-bounds read in Python - CVE-2024-5642

Vulnerability identifier: #VU97633

Vulnerability risk: Low

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

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: 3.7 - 3.7.17, 3.8 - 3.8.19, 3.9.0b4 - 3.9.19

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

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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.