From: dev <b.chouksey27@gmail.com>
Date: Tue, 23 Jun 2026 14:15:15 +0000 (+0530)
Subject: gh-151773: Fix NULL dereference in `PyContextVar_Set` (#151836)
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d35b1719a58c8682a22ef698e070e97661af8d14;p=thirdparty%2FPython%2Fcpython.git

gh-151773: Fix NULL dereference in `PyContextVar_Set` (#151836)
---

diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-06-21-16-00-00.gh-issue-151773.mN4kRt.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-06-21-16-00-00.gh-issue-151773.mN4kRt.rst
new file mode 100644
index 000000000000..b4193c5e15ff
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2026-06-21-16-00-00.gh-issue-151773.mN4kRt.rst
@@ -0,0 +1,2 @@
+Fix a crash in :func:`contextvars.ContextVar.set` when memory allocation
+fails.
diff --git a/Python/context.c b/Python/context.c
index 593e6ef90037..4678054ff3ad 100644
--- a/Python/context.c
+++ b/Python/context.c
@@ -362,6 +362,9 @@ PyContextVar_Set(PyObject *ovar, PyObject *val)
     Py_XINCREF(old_val);
     PyContextToken *tok = token_new(ctx, var, old_val);
     Py_XDECREF(old_val);
+    if (tok == NULL) {
+        return NULL;
+    }
 
     if (contextvar_set(var, val)) {
         Py_DECREF(tok);