CVE-2024-5642
Buffer overread when using an empty list with SSLContext.set_npn_protocols()
CVSS Score
6.5
EPSS Score
0.2%
EPSS Percentile
41th
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. This results in a buffer over-read when NPN is used (see CVE-2024-5535 for OpenSSL). This vulnerability is of low severity due to NPN being not widely used and specifying an empty list likely being uncommon in-practice (typically a protocol name would be configured).
| Vendor | python software foundation |
| Product | cpython |
| Published | Jun 27, 2024 |
| Last Updated | Apr 21, 2026 |
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Affected Versions
Python Software Foundation / CPython
0 < 3.10.0b1
References
jbp.io: https://jbp.io/2024/06/27/cve-2024-5535-openssl-memory-safety.html github.com: https://github.com/python/cpython/pull/23014 mail.python.org: https://mail.python.org/archives/list/[email protected]/thread/PLP2JI3PJY33YG6P5BZYSSNU66HASXBQ/ github.com: https://github.com/python/cpython/commit/39258d3595300bc7b952854c915f63ae2d4b9c3e openwall.com: http://www.openwall.com/lists/oss-security/2024/06/28/4 github.com: https://github.com/python/cpython/issues/121227 security.netapp.com: https://security.netapp.com/advisory/ntap-20240726-0005/ github.com: https://github.com/python/cpython/commit/a2cdbb6e8188ba9ba8b356b28d91bff60e86fe31