Loading vulnerability…
CVE-2026-19445 is a use-after-free vulnerability in CPython's server-side TLS context handling. When an sni_callback selects a certificate by assigning a different context to SSLSocket.context, the original ssl.SSLContext can be freed if no other reference retains it. A remote, unauthenticated TLS client can then cause the server to crash or call through a freed pointer. Typical affected configurations create SSLContext objects per connection or replace contexts while connections remain open. TLS clients and servers that wrap their listening socket with the original context are not affected.
Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
What an attacker gets, and what they’ve been doing with it.
If you can’t patch tonight, do this now.
Patch, then assume compromise.
1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
This eight-file repository is a self-contained Python/Docker proof of concept for CVE-2026-19445, a server-side CPython ssl use-after-free involving SNI callback context switching. The root Python launcher only renders a banner and invokes lab/run.sh. The Bash runner rebuilds a Docker Compose lab, executes lab/poc.py in a pinned Python 3.14.7 container (or falls back to host Python), saves a SUCCESS/FAIL witness line, and tears down the stack. The main lab uses MemoryBIO for the primary and secondary UAF oracles, rather than connecting to an external target. It arranges an SNI callback to replace SSLObject.context, forces a TLS 1.3 HelloRetryRequest using P-384, triggers garbage collection, and checks that the original dispatch SSLContext was released even though the handshake may complete. A loopback-only listener on 127.0.0.1:18500 is explicitly a negative control demonstrating that a process-lifetime listening context remains referenced. There is no RCE, reverse shell, persistence, credential theft, or arbitrary command payload.
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
12 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
An unspecified security vulnerability in the Python interpreter addressed by the Python 3.14.8 Fedora 43 update.
A security vulnerability in the Python interpreter addressed by the python3.14-3.14.8-1.fc44 Fedora 44 update. The specific vulnerability type and impact are not described.
A network-reachable vulnerability with high confidentiality, integrity, and availability impact under CVSS v3, affecting listed Debian Linux releases and PyPy3/Python package builds. The provided information does not describe the underlying flaw or affected version ranges.
A remote unauthenticated vulnerability affecting TLS servers using Python SSLContext SNI callbacks. If an sni_callback replaces SSLSocket.context and the original SSLContext is no longer referenced, an attacker can trigger a server crash or a call through a freed pointer. TLS clients and servers that wrap their listening socket with the context are not affected.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.