diff --git a/debian/patches/curl-Assert-that-curl_multi_assign-worked.patch b/debian/patches/curl-Assert-that-curl_multi_assign-worked.patch
new file mode 100644
index 00000000..bd84a278
--- /dev/null
+++ b/debian/patches/curl-Assert-that-curl_multi_assign-worked.patch
@@ -0,0 +1,31 @@
+From: Colin Walters <walters@verbum.org>
+Date: Wed, 18 Sep 2024 13:21:27 -0400
+Subject: curl: Assert that curl_multi_assign worked
+
+ref https://github.com/ostreedev/ostree/issues/3299
+
+This won't fix that issue, but *if* this assertion triggers
+it should give us a better idea of the possible codepaths
+where it is happening.
+
+Signed-off-by: Colin Walters <walters@verbum.org>
+Origin: upstream, 2024.8, commit:472d9d493a3e4a08415da4c337a7e831e0c5a5e2
+Bug-Debian: https://bugs.debian.org/1082121
+---
+ src/libostree/ostree-fetcher-curl.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/src/libostree/ostree-fetcher-curl.c b/src/libostree/ostree-fetcher-curl.c
+index d690289..5808c45 100644
+--- a/src/libostree/ostree-fetcher-curl.c
++++ b/src/libostree/ostree-fetcher-curl.c
+@@ -517,7 +517,8 @@ addsock (curl_socket_t s, CURL *easy, int action, OstreeFetcher *fetcher)
+   fdp->refcount = 1;
+   fdp->fetcher = fetcher;
+   setsock (fdp, s, action, fetcher);
+-  curl_multi_assign (fetcher->multi, s, fdp);
++  CURLMcode rc = curl_multi_assign (fetcher->multi, s, fdp);
++  g_assert_cmpint (rc, ==, CURLM_OK);
+   g_hash_table_add (fetcher->sockets, fdp);
+ }
+ 
diff --git a/debian/patches/curl-Make-socket-callback-during-cleanup-into-no-op.patch b/debian/patches/curl-Make-socket-callback-during-cleanup-into-no-op.patch
new file mode 100644
index 00000000..cb3f72f2
--- /dev/null
+++ b/debian/patches/curl-Make-socket-callback-during-cleanup-into-no-op.patch
@@ -0,0 +1,62 @@
+From: Colin Walters <walters@verbum.org>
+Date: Wed, 18 Sep 2024 13:41:59 -0400
+Subject: curl: Make socket callback during cleanup into no-op
+
+Because curl_multi_cleanup may invoke callbacks, we effectively have
+some circular references going on here. See discussion in
+
+https://github.com/curl/curl/issues/14860
+
+Basically what we do is the socket callback libcurl may invoke into a no-op when
+we detect we're finalizing. The data structures are owned by this object and
+not by the callbacks, and will be destroyed below. Note that
+e.g. g_hash_table_unref() may itself invoke callbacks, which is where
+some data is cleaned up.
+
+Signed-off-by: Colin Walters <walters@verbum.org>
+Origin: upstream, 2024.8, commit:4d755a85225ea0a02d4580d088bb8a97138cb040
+Bug: https://github.com/ostreedev/ostree/issues/3299
+Bug-Debian: https://bugs.debian.org/1082121
+---
+ src/libostree/ostree-fetcher-curl.c | 14 ++++++++++++++
+ 1 file changed, 14 insertions(+)
+
+diff --git a/src/libostree/ostree-fetcher-curl.c b/src/libostree/ostree-fetcher-curl.c
+index 5808c45..1872974 100644
+--- a/src/libostree/ostree-fetcher-curl.c
++++ b/src/libostree/ostree-fetcher-curl.c
+@@ -78,6 +78,7 @@ struct OstreeFetcher
+   struct curl_slist *extra_headers;
+   int tmpdir_dfd;
+   bool force_anonymous;
++  bool finalizing; // Set if we're in the process of teardown
+   char *custom_user_agent;
+   guint32 opt_low_speed_limit;
+   guint32 opt_low_speed_time;
+@@ -180,6 +181,15 @@ _ostree_fetcher_finalize (GObject *object)
+ {
+   OstreeFetcher *self = OSTREE_FETCHER (object);
+ 
++  // Because curl_multi_cleanup may invoke callbacks, we effectively have
++  // some circular references going on here. See discussion in
++  // https://github.com/curl/curl/issues/14860
++  // Basically what we do is make most callbacks libcurl may invoke into no-ops when
++  // we detect we're finalizing. The data structures are owned by this object and
++  // not by the callbacks, and will be destroyed below. Note that
++  // e.g. g_hash_table_unref() may itself invoke callbacks, which is where
++  // some data is cleaned up.
++  self->finalizing = true;
+   curl_multi_cleanup (self->multi);
+   g_free (self->remote_name);
+   g_free (self->tls_ca_db_path);
+@@ -529,6 +539,10 @@ sock_cb (CURL *easy, curl_socket_t s, int what, void *cbp, void *sockp)
+   OstreeFetcher *fetcher = cbp;
+   SockInfo *fdp = (SockInfo *)sockp;
+ 
++  // We do nothing if we're in the process of teardown; see below.
++  if (fetcher->finalizing)
++    return 0;
++
+   if (what == CURL_POLL_REMOVE)
+     {
+       if (!g_hash_table_remove (fetcher->sockets, fdp))
diff --git a/debian/patches/series b/debian/patches/series
index 78a4e054..50cb91d2 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -1,3 +1,5 @@
+curl-Assert-that-curl_multi_assign-worked.patch
+curl-Make-socket-callback-during-cleanup-into-no-op.patch
 debian/Skip-test-pull-repeated-during-CI.patch
 debian/test-sysroot-Skip-on-s390x-by-default.patch
 debian/Skip-test-admin-deploy-uboot.sh-on-s390x.patch