SC426 · Oct 29, 2026 · Oct 29, 2026 · Oct 29, 2026
diff --git a/anaconda.yaml b/anaconda.yaml
@@ -0,0 +1,9 @@
+anaconda_config_version: 1
+upstream_sources:
+  - webpage:
+      url: https://www.python.org/ftp/python/
+      regex: href="(\d+(?:\.\d+)+)/"
+      include_regex: ^3\.10\.\d+(?:[a-z][a-z0-9]*)?$
+    packages:
+      - python
+      - libpython-static
diff --git a/recipe/meta.yaml b/recipe/meta.yaml
@@ -4,7 +4,7 @@
 {% set ver2 = '.'.join(version.split('.')[0:2]) %}
 {% set ver2nd = ''.join(version.split('.')[0:2]) %}
 {% set ver3nd = ''.join(version.split('.')[0:3]) %}
-{% set build_number = "0" %}
+{% set build_number = "1" %}
 {% set channel_targets = ('abc', 'def')  %}
 
 # this makes the linter happy
@@ -90,6 +90,10 @@ source:
       - patches/0027-Unvendor-expat.patch
       # https://github.com/python/cpython/pull/29791
       - patches/0029-Fix-ctypes-fielddesc-init-for-external-libffi.patch
+      # CVE-2026-115557 (gh-160040): distrust compromised eMudhra intermediate
+      # CA keys. Backport of CPython 3.11 commit 7dd8b4736a1419750b94a388e6d158be15836fe6;
+      # 3.10 is EOL, so upstream has no fixed 3.10 release.
+      - patches/0030-Distrust-compromised-eMudhra-intermediate-CA-keys.patch
 
 build:
   number: {{ build_number }}
@@ -110,6 +114,8 @@ outputs:
     script: build_base.bat  # [win]
     build:
       number: {{ build_number }}
+      # win-arm64 ships Python >=3.12 only (aggregate CBC)
+      skip: true  # [win and arm64]
       activate_in_script: true
       # Windows has issues updating python if conda is using files itself.
       # Copy rather than link.
@@ -236,6 +242,7 @@ outputs:
         - tests/cmake/*
         - tests/cython/*
         - tests/prefix-replacement/*
+        - tests/ssl/*
         - run_test.py
         - test-cert.pem
       commands:
@@ -301,6 +308,8 @@ outputs:
     script: build_static.bat  # [win]
     build:
       number: {{ build_number }}
+      # win-arm64 ships Python >=3.12 only (aggregate CBC)
+      skip: true  # [win and arm64]
       activate_in_script: true
 {% if 'conda-forge' in channel_targets %}
       ignore_run_exports:

diff --git a/recipe/patches/0030-Distrust-compromised-eMudhra-intermediate-CA-keys.patch b/recipe/patches/0030-Distrust-compromised-eMudhra-intermediate-CA-keys.patch
@@ -0,0 +1,249 @@
+From b299e19c65e03a6c3df58b31f9da4e1f974c81a5 Mon Sep 17 00:00:00 2001
+From: Christian Heimes <christian@python.org>
+Date: Thu, 29 Oct 2026 11:09:28 -0600
+Subject: [PATCH] gh-160040: Distrust compromised eMudhra intermediate CA keys
+ (CVE-2026-115557)
+
+Backport of the 3.11 fix (commit 7dd8b4736a1419750b94a388e6d158be15836fe6,
+PR gh-160042) to 3.10, which reached end of life before a fixed release
+was published.  Adds a denylist of compromised SubjectPublicKeyInfo
+SHA-256 digests and installs a verify callback that rejects any peer chain
+containing one of those keys.
+
+Adapted for 3.10: no Makefile.pre.in MODULE__SSL_DEPS entry exists and the
+older Visual Studio project layout is used, so the Visual Studio header
+entries are added without the upstream ItemGroup reordering.
+
+(cherry picked from commit 7dd8b4736a1419750b94a388e6d158be15836fe6)
+---
+ Modules/_ssl.c                 | 67 ++++++++++++++++++++++++++++--
+ Modules/_ssl/distrusted_spki.h | 75 ++++++++++++++++++++++++++++++++++
+ PCbuild/_ssl.vcxproj           |  3 ++
+ PCbuild/_ssl.vcxproj.filters   |  8 ++++
+ 4 files changed, 149 insertions(+), 4 deletions(-)
+ create mode 100644 Modules/_ssl/distrusted_spki.h
+
+diff --git a/Modules/_ssl.c b/Modules/_ssl.c
+index d58bb15..2b409bb 100644
+--- a/Modules/_ssl.c
++++ b/Modules/_ssl.c
+@@ -54,6 +54,7 @@
+ /* Include OpenSSL header files */
+ #include "openssl/rsa.h"
+ #include "openssl/crypto.h"
++#include "openssl/evp.h"
+ #include "openssl/x509.h"
+ #include "openssl/x509v3.h"
+ #include "openssl/pem.h"
+@@ -880,6 +881,7 @@ newPySSLSocket(PySSLContext *sslctx, PySocketSockObject *sock,
+                 int (*verify_cb)(int, X509_STORE_CTX *) = NULL;
+                 verify_cb = SSL_get_verify_callback(self->ssl);
+                 mode |= SSL_VERIFY_POST_HANDSHAKE;
++                /* Keep ctx verify callback (distrusted SPKI check) */
+                 SSL_set_verify(self->ssl, mode, verify_cb);
+             }
+         } else {
+@@ -2985,11 +2987,70 @@ static PyType_Spec PySSLSocket_spec = {
+  * _SSLContext objects
+  */
+
++#include "_ssl/distrusted_spki.h"
++
++/* Returns 1 if the SHA-256 of the cert's SPKI is on the distrusted list,
++   0 if not (okay), -1 on an internal error. */
++static int
++_cert_has_distrusted_spki(X509 *cert)
++{
++    unsigned char *spki = NULL;
++    int spki_len = i2d_X509_PUBKEY(X509_get_X509_PUBKEY(cert), &spki);
++    if (spki_len <= 0 || spki == NULL) {
++        return -1;
++    }
++
++    unsigned char digest[EVP_MAX_MD_SIZE];
++    unsigned int digest_len = 0;
++    int ok = EVP_Digest(spki, (size_t)spki_len, digest, &digest_len,
++                        EVP_sha256(), NULL);
++    OPENSSL_free(spki);
++    assert(sizeof(_distrusted_spki[0]) == SHA256_DIGEST_LENGTH);
++    if (!ok
++        || digest_len != SHA256_DIGEST_LENGTH
++        || sizeof(_distrusted_spki[0]) != SHA256_DIGEST_LENGTH) {
++        return -1;
++    }
++
++    for (size_t i = 0; i < Py_ARRAY_LENGTH(_distrusted_spki); i++) {
++        if (memcmp(digest, _distrusted_spki[i], SHA256_DIGEST_LENGTH) == 0) {
++            return 1;
++        }
++    }
++    return 0;
++}
++
++/* Verify callback, called once per cert. Reject distrusted SPKIs. */
++static int
++_ssl_verify_callback(int preverify_ok, X509_STORE_CTX *x509_ctx)
++{
++    /* Don't override an error OpenSSL already reported for this certificate. */
++    if (!preverify_ok) {
++        return preverify_ok;
++    }
++    X509 *cert = X509_STORE_CTX_get_current_cert(x509_ctx);
++    if (cert == NULL) {
++        return preverify_ok;
++    }
++    switch (_cert_has_distrusted_spki(cert)) {
++    case 0:
++        /* okay: not on the distrusted list */
++        return preverify_ok;
++    case 1:
++        /* rejected: public key is on the distrusted list */
++        X509_STORE_CTX_set_error(x509_ctx, X509_V_ERR_CERT_REJECTED);
++        return 0;
++    default:
++        /* internal error */
++        X509_STORE_CTX_set_error(x509_ctx, X509_V_ERR_UNSPECIFIED);
++        return 0;
++    }
++}
++
+ static int
+ _set_verify_mode(PySSLContext *self, enum py_ssl_cert_requirements n)
+ {
+     int mode;
+-    int (*verify_cb)(int, X509_STORE_CTX *) = NULL;
+
+     switch(n) {
+     case PY_SSL_CERT_NONE:
+@@ -3010,9 +3071,7 @@ _set_verify_mode(PySSLContext *self, enum py_ssl_cert_requirements n)
+     /* bpo-37428: newPySSLSocket() sets SSL_VERIFY_POST_HANDSHAKE flag for
+      * server sockets and SSL_set_post_handshake_auth() for client. */
+
+-    /* keep current verify cb */
+-    verify_cb = SSL_CTX_get_verify_callback(self->ctx);
+-    SSL_CTX_set_verify(self->ctx, mode, verify_cb);
++    SSL_CTX_set_verify(self->ctx, mode, _ssl_verify_callback);
+     return 0;
+ }
+
+diff --git a/Modules/_ssl/distrusted_spki.h b/Modules/_ssl/distrusted_spki.h
+new file mode 100644
+index 0000000..bbdb56d
+--- /dev/null
++++ b/Modules/_ssl/distrusted_spki.h
+@@ -0,0 +1,75 @@
++/* Denylist of distrusted SubjectPublicKeyInfo (SPKI).
++ *
++ * Verification rejects any chain with a cert whose SPKI SHA-256 digest is in
++ * the _distrusted_spki table.  We match the key, not a cert fingerprint, so
++ * cross-signs that reuse the key are blocked too.
++ *
++ * This is an extraordinary measure and last line of defense.  Removing trust is
++ * primarily the job of the platform root store. This list only blocks keys while
++ * that update is still propagating to the OS, container images, or root CAs
++ * bundled in Python packages.  The threshold for adding an entry is very high.
++  *
++ * See https://github.com/python/cpython/issues/160040 for the eMudhra discussion.
++ *
++ * To block another key, add the SHA-256 digest bytes of its SPKI:
++ *
++ *     $ openssl x509 -in cert.pem -noout -pubkey | openssl pkey -pubin -outform DER | openssl dgst -sha256 -binary | xxd -i
++ */
++#ifndef Py_SSL_DISTRUSTED_SPKI_H
++#define Py_SSL_DISTRUSTED_SPKI_H
++
++#include "openssl/sha.h"
++
++static const unsigned char _distrusted_spki[][SHA256_DIGEST_LENGTH] = {
++    /* Compromised eMudhra intermediates, https://emudhra.we-have-a-problem.com/ */
++    /* CN=EM OV TLS CA - G3B,O=eMudhra BV,C=NL */
++    {
++        0x43, 0xbf, 0xfa, 0x19, 0xd6, 0xef, 0x65, 0x14, 0x51, 0xf6, 0x84, 0x1e,
++        0x01, 0x99, 0x31, 0xe9, 0x6f, 0x6f, 0x2e, 0xae, 0xff, 0x28, 0xab, 0x4b,
++        0x6f, 0x1c, 0xe4, 0x57, 0x6d, 0xe2, 0x71, 0x7b,
++    },
++    /* CN=EM DV TLS CA - G3C,O=eMudhra Inc,C=US */
++    {
++        0x49, 0xdd, 0x35, 0x3d, 0xc2, 0xb9, 0x19, 0xa3, 0x77, 0x06, 0x45, 0x11,
++        0x7d, 0x0e, 0x60, 0xc1, 0x61, 0x15, 0xe7, 0xd1, 0xbc, 0x25, 0x9e, 0xef,
++        0xe7, 0x34, 0xb0, 0x0e, 0xa4, 0x34, 0xfe, 0x5f,
++    },
++    /* CN=EM EV TLS CA - G3C,O=eMudhra Inc,C=US */
++    {
++        0x5c, 0x06, 0x60, 0xa2, 0xb1, 0x64, 0x91, 0x0d, 0x8f, 0xf5, 0x89, 0xc1,
++        0x8e, 0x14, 0x55, 0x2e, 0x9e, 0x0e, 0xc2, 0x37, 0xdc, 0xef, 0xe2, 0xcb,
++        0x73, 0x6d, 0x41, 0xa4, 0x81, 0x1f, 0x81, 0xa0,
++    },
++    /* CN=EM OV TLS CA - G3C,O=eMudhra Inc,C=US */
++    {
++        0x63, 0xec, 0xef, 0xee, 0x43, 0x1d, 0x49, 0x52, 0x3b, 0xc1, 0x13, 0x6c,
++        0x4e, 0x72, 0xd0, 0x20, 0x6a, 0x47, 0x70, 0x86, 0xca, 0xf6, 0x06, 0xcd,
++        0x5c, 0xf0, 0x25, 0x68, 0x6c, 0x10, 0x9c, 0xf8,
++    },
++    /* CN=EM OV CS CA - G3C,O=eMudhra Inc,C=US */
++    {
++        0x92, 0xc0, 0x63, 0xd6, 0x7e, 0x8f, 0x14, 0xdb, 0x71, 0xd2, 0x88, 0xe1,
++        0x12, 0x66, 0xff, 0xda, 0xf6, 0x9c, 0xbf, 0x11, 0x5f, 0x7b, 0xab, 0x14,
++        0xf3, 0xbc, 0x2f, 0x68, 0xd2, 0x5e, 0x0e, 0x30,
++    },
++    /* CN=EM EV TLS CA - G3B,O=eMudhra BV,C=NL */
++    {
++        0xe0, 0x25, 0x4c, 0x7f, 0xcd, 0xc2, 0x65, 0xe2, 0xf0, 0xf8, 0xa4, 0x28,
++        0xda, 0xbb, 0x75, 0xab, 0x4a, 0xe0, 0x39, 0xb4, 0x87, 0x2d, 0x62, 0xf5,
++        0xee, 0x57, 0xf0, 0x87, 0x7d, 0x5a, 0x8a, 0x41,
++    },
++    /* CN=EM DV TLS CA - G3B,O=eMudhra BV,C=NL */
++    {
++        0xeb, 0xed, 0x64, 0x75, 0xc2, 0xc2, 0xd8, 0x0f, 0xcb, 0x19, 0x9f, 0x3f,
++        0xe8, 0xdd, 0x6e, 0x6b, 0x3c, 0xe6, 0x0b, 0x77, 0xeb, 0x15, 0xd4, 0xe4,
++        0x2c, 0x3d, 0xec, 0x0c, 0x6f, 0x5b, 0x51, 0x05,
++    },
++    /* CN=EM OV CS CA - G3B,O=eMudhra BV,C=NL */
++    {
++        0xec, 0x4f, 0xfa, 0x1a, 0xd0, 0xac, 0x88, 0x08, 0x13, 0x14, 0xb7, 0xaa,
++        0xff, 0xef, 0x6a, 0x91, 0xf9, 0x7c, 0xd5, 0x72, 0x91, 0xbb, 0x5b, 0xa6,
++        0x86, 0xc5, 0x41, 0x5f, 0x5e, 0xb4, 0xf6, 0xb6,
++    },
++};
++
++#endif /* !Py_SSL_DISTRUSTED_SPKI_H */
+diff --git a/PCbuild/_ssl.vcxproj b/PCbuild/_ssl.vcxproj
+index f583d57..75bec7c 100644
+--- a/PCbuild/_ssl.vcxproj
++++ b/PCbuild/_ssl.vcxproj
+@@ -109,6 +109,9 @@
+       <AdditionalOptions Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">/d1trimfile:%SRC_DIR%</AdditionalOptions>
+     </ClCompile>
+   </ItemDefinitionGroup>
++  <ItemGroup>
++    <ClInclude Include="..\Modules\_ssl\distrusted_spki.h" />
++  </ItemGroup>
+   <ItemGroup>
+     <ClCompile Include="..\Modules\_ssl.c" />
+   </ItemGroup>
+diff --git a/PCbuild/_ssl.vcxproj.filters b/PCbuild/_ssl.vcxproj.filters
+index 2f631dc..37c9202 100644
+--- a/PCbuild/_ssl.vcxproj.filters
++++ b/PCbuild/_ssl.vcxproj.filters
+@@ -4,6 +4,9 @@
+     <Filter Include="Source Files">
+       <UniqueIdentifier>{695348f7-e9f6-4fe1-bc03-5f08ffc8095b}</UniqueIdentifier>
+     </Filter>
++    <Filter Include="Header Files">
++      <UniqueIdentifier>{7c1bd5da-8912-4107-b6ac-f3930f2d90c7}</UniqueIdentifier>
++    </Filter>
+     <Filter Include="Resource Files">
+       <UniqueIdentifier>{1b18a2e6-040d-46c7-a9ac-ac2ec64fb5d6}</UniqueIdentifier>
+     </Filter>
+@@ -13,6 +16,11 @@
+       <Filter>Source Files</Filter>
+     </ClCompile>
+   </ItemGroup>
++  <ItemGroup>
++    <ClInclude Include="..\Modules\_ssl\distrusted_spki.h">
++      <Filter>Header Files</Filter>
++    </ClInclude>
++  </ItemGroup>
+   <ItemGroup>
+     <ResourceCompile Include="..\PC\python_nt.rc">
+       <Filter>Resource Files</Filter>
diff --git a/recipe/run_test.py b/recipe/run_test.py
@@ -104,3 +104,45 @@
 der = ssl.PEM_cert_to_DER_cert(pem)
 ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
 ctx.load_verify_locations(cadata=der)
+
+# CVE-2026-115557 (gh-160040): a peer chain signed by a compromised eMudhra
+# intermediate must be rejected even though the chain itself is valid.
+import tempfile
+import zipfile
+
+fixtures = Path(__file__).with_name("tests") / "ssl"
+with tempfile.TemporaryDirectory() as tmpdir:
+    # The archive is encrypted only so the test certs are not stored in the
+    # clear; the password is fixed and public.
+    with zipfile.ZipFile(fixtures / "distrusted.zip") as zf:
+        zf.extractall(tmpdir, pwd=b"Brave Sir Robin")
+    distrusted = Path(tmpdir) / "distrusted"
+    client_ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
+    server_ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
+    client_ctx.load_verify_locations(str(distrusted / "distrusted_root.pem"))
+    server_ctx.load_cert_chain(str(distrusted / "distrusted_keycert.pem"))
+
+    c_in, c_out = ssl.MemoryBIO(), ssl.MemoryBIO()
+    s_in, s_out = ssl.MemoryBIO(), ssl.MemoryBIO()
+    client = client_ctx.wrap_bio(c_in, c_out, server_hostname="localhost")
+    server = server_ctx.wrap_bio(s_in, s_out, server_side=True)
+    try:
+        for _ in range(5):
+            try:
+                client.do_handshake()
+            except ssl.SSLWantReadError:
+                pass
+            if c_out.pending:
+                s_in.write(c_out.read())
+            try:
+                server.do_handshake()
+            except ssl.SSLWantReadError:
+                pass
+            if s_out.pending:
+                c_in.write(s_out.read())
+        client.do_handshake()
+    except ssl.SSLCertVerificationError as exc:
+        assert exc.verify_code == 28, exc  # X509_V_ERR_CERT_REJECTED
+    else:
+        raise AssertionError("distrusted eMudhra chain was accepted")
+print("distrusted SPKI check: OK")
diff --git a/recipe/tests/ssl/distrusted.zip b/recipe/tests/ssl/distrusted.zip