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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-re…

Medium CVSS 6.5
CVECVE-2024-5642
First seen2026-07-31 16:30 UTC
Disclosed2024-06-27 21:15 UTC
Last updated2026-07-31 16:30 UTC
Channel statusauto

Summary

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).

In-depth triage · Auto channel

No in-depth report has been generated yet (DR-003 v2 AI pipeline is under construction).

Lint boundary warnings (2)

The following non-blocking warnings were raised during the lint phase of this triage (e.g. reference URLs not yet on the allowlist). They do not affect entry usability and are disclosed for transparency (see DR-002).

  • REF_URL_NOT_ALLOWLISTED url not in allowlist: https://jbp.io/2024/06/27/cve-2024-5535-openssl-memory-safety.html
  • REF_URL_NOT_ALLOWLISTED url not in allowlist: https://jbp.io/2024/06/27/cve-2024-5535-openssl-memory-safety.html

Sources

  • NVD DATABASE

Original Links

Timeline

  1. nvd_ingest NVD