From: Ramin Farajpour Cami <ramin.blackhat@gmail.com>
Date: Mon, 16 Feb 2026 02:43:07 +0000 (+0330)
Subject: gh-144833: Fix use-after-free in SSL module when SSL_new() fails (GH-144843)
X-Git-Tag: v3.15.0a7~272
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=c91638ca0671b8038831f963ed44e66cdda006a2;p=thirdparty%2FPython%2Fcpython.git

gh-144833: Fix use-after-free in SSL module when SSL_new() fails (GH-144843)

In newPySSLSocket(), when SSL_new() returns NULL, Py_DECREF(self)
was called before _setSSLError(get_state_ctx(self), ...), causing
a use-after-free. Additionally, get_state_ctx() was called with
self (PySSLSocket*) instead of sslctx (PySSLContext*), which is
a type confusion bug.

Fix by calling _setSSLError() before Py_DECREF() and using
sslctx instead of self for get_state_ctx().
---

diff --git a/Misc/NEWS.d/next/Library/2026-02-15-00-00-00.gh-issue-144833.TUelo1.rst b/Misc/NEWS.d/next/Library/2026-02-15-00-00-00.gh-issue-144833.TUelo1.rst
new file mode 100644
index 000000000000..6d5b18f59ee7
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-02-15-00-00-00.gh-issue-144833.TUelo1.rst
@@ -0,0 +1,3 @@
+Fixed a use-after-free in :mod:`ssl` when ``SSL_new()`` returns NULL in
+``newPySSLSocket()``. The error was reported via a dangling pointer after the
+object had already been freed.
diff --git a/Modules/_ssl.c b/Modules/_ssl.c
index 66d699b4339c..b0c0d8deeecd 100644
--- a/Modules/_ssl.c
+++ b/Modules/_ssl.c
@@ -917,8 +917,8 @@ newPySSLSocket(PySSLContext *sslctx, PySocketSockObject *sock,
     self->ssl = SSL_new(ctx);
     PySSL_END_ALLOW_THREADS(sslctx)
     if (self->ssl == NULL) {
+        _setSSLError(get_state_ctx(sslctx), NULL, 0, __FILE__, __LINE__);
         Py_DECREF(self);
-        _setSSLError(get_state_ctx(self), NULL, 0, __FILE__, __LINE__);
         return NULL;
     }