diff --git a/Cargo.lock b/Cargo.lock
index a63df40cea..e7ecd2fcd4 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2875,8 +2875,7 @@ dependencies = [
 [[package]]
 name = "iroh-quinn"
 version = "0.14.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0cde160ebee7aabede6ae887460cd303c8b809054224815addf1469d54a6fcf7"
+source = "git+https://github.com/zakura-core/iroh-quinn?rev=1dcc7a43488fecd199d343d47e93e9ed8319fcaa#1dcc7a43488fecd199d343d47e93e9ed8319fcaa"
 dependencies = [
  "bytes",
  "cfg_aliases",
@@ -2895,8 +2894,7 @@ dependencies = [
 [[package]]
 name = "iroh-quinn-proto"
 version = "0.13.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "929d5d8fa77d5c304d3ee7cae9aede31f13908bd049f9de8c7c0094ad6f7c535"
+source = "git+https://github.com/zakura-core/iroh-quinn?rev=1dcc7a43488fecd199d343d47e93e9ed8319fcaa#1dcc7a43488fecd199d343d47e93e9ed8319fcaa"
 dependencies = [
  "bytes",
  "getrandom 0.2.17",
@@ -2915,8 +2913,7 @@ dependencies = [
 [[package]]
 name = "iroh-quinn-udp"
 version = "0.5.7"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c53afaa1049f7c83ea1331f5ebb9e6ebc5fdd69c468b7a22dd598b02c9bcc973"
+source = "git+https://github.com/zakura-core/iroh-quinn?rev=1dcc7a43488fecd199d343d47e93e9ed8319fcaa#1dcc7a43488fecd199d343d47e93e9ed8319fcaa"
 dependencies = [
  "cfg_aliases",
  "libc",
diff --git a/Cargo.toml b/Cargo.toml
index e2a6f62523..5fb224f178 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -35,6 +35,14 @@ keywords = ["zakura", "zcash"]
 rust-version = "1.97"
 edition = "2021"
 
+# Backport the loss-probe datagram limit fix to Iroh 0.92's exact QUIC versions.
+# Keep the related crates on one revision. Workspace patches are not inherited
+# by downstream library users; they must apply the same patch in their workspace.
+[patch.crates-io]
+iroh-quinn = { git = "https://github.com/zakura-core/iroh-quinn", rev = "1dcc7a43488fecd199d343d47e93e9ed8319fcaa" }
+iroh-quinn-proto = { git = "https://github.com/zakura-core/iroh-quinn", rev = "1dcc7a43488fecd199d343d47e93e9ed8319fcaa" }
+iroh-quinn-udp = { git = "https://github.com/zakura-core/iroh-quinn", rev = "1dcc7a43488fecd199d343d47e93e9ed8319fcaa" }
+
 [workspace.dependencies]
 # Zakura's published binary assets: the reviewed Mainnet historical frontier grid, which is too
 # large to carry in git history at the weekly cadence the release state advances.
diff --git a/crates/zakura-network/src/zakura/handler.rs b/crates/zakura-network/src/zakura/handler.rs
index fefcf45e87..2541103429 100644
--- a/crates/zakura-network/src/zakura/handler.rs
+++ b/crates/zakura-network/src/zakura/handler.rs
@@ -5465,6 +5465,7 @@ impl ZakuraHandlerError {
 
 #[cfg(test)]
 mod tests {
+    mod quic_progress;
     use super::*;
     use crate::{
         protocol::internal::{InventoryResponse, Response},
diff --git a/crates/zakura-network/src/zakura/handler/tests/quic_progress.rs b/crates/zakura-network/src/zakura/handler/tests/quic_progress.rs
new file mode 100644
index 0000000000..cd5b0508ba
--- /dev/null
+++ b/crates/zakura-network/src/zakura/handler/tests/quic_progress.rs
@@ -0,0 +1,83 @@
+//! Regression coverage for the pinned QUIC loss-recovery backport.
+
+use super::*;
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn bidirectional_transfers_exceed_flow_control_windows() -> Result<(), BoxError> {
+    let _guard = zakura_test::init();
+    const ALPN: &[u8] = b"/zakura/testkit/quic-progress/0";
+    // Larger than the default send, stream, and connection windows. Both sides
+    // must receive acknowledgements and new flow-control credit to finish.
+    const BYTES: usize = 64 * 1024 * 1024;
+    let limits = ZakuraLocalLimits::from_config(&Config::default());
+    let server = LocalEndpointFactory::with_transport_config(limits.transport_config())
+        .endpoint(92341)
+        .await?;
+    let client = LocalEndpointFactory::with_transport_config(limits.transport_config())
+        .endpoint(92342)
+        .await?;
+    let (connection_tx, mut connection_rx) = mpsc::channel(1);
+    let (stream_tx, mut stream_rx) = mpsc::channel(1);
+    let router = Router::builder(server)
+        .accept(
+            ALPN,
+            CaptureConnection {
+                connection_tx,
+                stream_tx,
+            },
+        )
+        .spawn();
+    let address = LocalEndpointFactory::node_addr(router.endpoint()).await;
+    let connection = timeout(Duration::from_secs(10), client.connect(address, ALPN)).await??;
+    let remote = timeout(Duration::from_secs(5), connection_rx.recv())
+        .await?
+        .unwrap();
+    let (mut send_a, recv_a) = connection.open_bi().await?;
+    // Make the stream visible to accept_bi before starting the bulk transfer.
+    send_a.write_all(&[42]).await?;
+    let (mut send_b, recv_b) = timeout(Duration::from_secs(5), stream_rx.recv())
+        .await?
+        .unwrap();
+
+    let transfer = async {
+        tokio::try_join!(
+            async {
+                send_a.write_all(&vec![42; BYTES]).await?;
+                send_a.finish()?;
+                Ok::<_, BoxError>(())
+            },
+            async {
+                send_b.write_all(&vec![43; BYTES]).await?;
+                send_b.finish()?;
+                Ok::<_, BoxError>(())
+            },
+            drain_stream(recv_a, BYTES, 43),
+            drain_stream(recv_b, BYTES + 1, 42),
+        )?;
+        Ok::<_, BoxError>(())
+    };
+    timeout(Duration::from_secs(30), transfer)
+        .await
+        .unwrap_or_else(|_| {
+            panic!(
+                "QUIC transfer stalled: local={:?}; remote={:?}",
+                connection.stats(),
+                remote.stats()
+            )
+        })?;
+    connection.close(0u32.into(), b"done");
+    client.close().await;
+    router.shutdown().await?;
+    Ok(())
+}
+
+async fn drain_stream(mut recv: RecvStream, expected: usize, byte: u8) -> Result<(), BoxError> {
+    let mut buffer = vec![0; 64 * 1024];
+    let mut received = 0;
+    while let Some(count) = recv.read(&mut buffer).await? {
+        assert!(buffer[..count].iter().all(|value| *value == byte));
+        received += count;
+        assert!(received <= expected);
+    }
+    assert_eq!(received, expected);
+    Ok(())
+}
diff --git a/deny.toml b/deny.toml
index b98c213547..d28975ad68 100644
--- a/deny.toml
+++ b/deny.toml
@@ -210,7 +210,7 @@ unknown-git = "deny"
 allow-registry = ["https://github.com/rust-lang/crates.io-index"]
 
 # List of URLs for allowed Git repositories
-allow-git = []
+allow-git = ["https://github.com/zakura-core/iroh-quinn"]
 
 [sources.allow-org]
 github = [
diff --git a/docs/changelog/unreleased/941.md b/docs/changelog/unreleased/941.md
new file mode 100644
index 0000000000..3ab1af39c0
--- /dev/null
+++ b/docs/changelog/unreleased/941.md
@@ -0,0 +1,5 @@
+## Fixed
+
+- Fix QUIC connections stalling during loss recovery when the socket cannot
+  send a batch of datagrams
+  ([#941](https://github.com/zakura-core/zakura/pull/941)).
diff --git a/qa/supply-chain/audits.toml b/qa/supply-chain/audits.toml
index 7415a56665..672460e02f 100644
--- a/qa/supply-chain/audits.toml
+++ b/qa/supply-chain/audits.toml
@@ -4381,3 +4381,24 @@ criteria = "safe-to-deploy"
 user-id = 169181 # Kris Nuttycombe (nuttycom)
 start = "2024-12-17"
 end = "2027-07-10"
+
+[[audits.iroh-quinn]]
+who = "OpenAI Codex <noreply@openai.com>"
+criteria = "safe-to-deploy"
+delta = "0.14.0 -> 0.14.0@git:1dcc7a43488fecd199d343d47e93e9ed8319fcaa"
+importable = false
+notes = "Compared the 25 packaged files, including the original manifest, with the pinned Git source. They are byte-identical to the already audited registry release. The related protocol crate carries the separately audited loss-recovery fix."
+
+[[audits.iroh-quinn-proto]]
+who = "OpenAI Codex <noreply@openai.com>"
+criteria = "safe-to-deploy"
+delta = "0.13.0 -> 0.13.0@git:1dcc7a43488fecd199d343d47e93e9ed8319fcaa"
+importable = false
+notes = "Compared all 53 packaged files with the pinned source. Only the transmit-bound condition and its regression test differ. The condition counts datagrams directly instead of inferring their count from bytes, so a short loss probe cannot admit a second datagram when the socket supports only one. The integer conversion is bounded by the existing ten-segment clamp. The regression failed on the original condition; all 254 default-feature protocol tests pass with the fix. No parsing, cryptography, dependency, or unsafe-code changes."
+
+[[audits.iroh-quinn-udp]]
+who = "OpenAI Codex <noreply@openai.com>"
+criteria = "safe-to-deploy"
+delta = "0.5.7 -> 0.5.7@git:1dcc7a43488fecd199d343d47e93e9ed8319fcaa"
+importable = false
+notes = "Compared the 13 packaged files, including the original manifest and build script, with the pinned Git source. They are byte-identical to the already audited registry release. Socket and platform-specific code is unchanged."
diff --git a/qa/supply-chain/config.toml b/qa/supply-chain/config.toml
index 62b0022789..c192e21d4c 100644
--- a/qa/supply-chain/config.toml
+++ b/qa/supply-chain/config.toml
@@ -28,6 +28,16 @@ url = "https://raw.githubusercontent.com/zcash/rust-ecosystem/main/supply-chain/
 [imports.zcashd]
 url = "https://raw.githubusercontent.com/zcash/zcash/master/qa/supply-chain/audits.toml"
 
+# Keep the existing registry audits and require a reviewed delta for the backport.
+[policy.iroh-quinn]
+audit-as-crates-io = true
+
+[policy.iroh-quinn-proto]
+audit-as-crates-io = true
+
+[policy.iroh-quinn-udp]
+audit-as-crates-io = true
+
 [policy.zakura]
 audit-as-crates-io = false