CVE-2026-19445: Python Software Foundation CPython vulnerability
Python Software Foundation · CPython
Vendor fix available · Affected: Python Software Foundation CPython · Exploitation: public proof of concept (unverified)
ExploitationProof of concept public
Not in CISA KEV as of catalogue 2026.11.13 (13 Nov)
- In CISA KEV: not seen
- Exploited (reported): not seen
- Scanning observed: not seen
- Proof of concept public1 public GitHub repository (unverified), listed by PoC-in-GitHub2 Oct
- Not established: not seen
Higher than 45% of scored CVEs
DescriptionNVD
A remote, unauthenticated TLS client can make a server crash or call through a freed pointer if its sni_callback assigns a different context to SSLSocket.context (the documented way to select a certificate per server name) and nothing else keeps the original ssl.SSLContext alive. Typical cases are servers that create an SSLContext per connection or replace it while connections are open; servers that wrap their listening socket with it are not affected. Mitigation: keep a reference to every SSLContext that sets sni_callback for the lifetime of the server. TLS clients are not affected.
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Unlikely (under 1%). EPSS under 1%, or no score yet.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Published
- September 2026
What changed
- PoC-in-GitHub lists 1 public GitHub repository (unverified) PoC-in-GitHub
Coverage1 article · 1 outlet
First in our coverage: SecurityOnline, 1 Oct.
- Python Fixes Critical SSL Flaws Threatening TLS SecuritySecurityOnline · first in our coverage
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