diff --git a/Cargo.lock b/Cargo.lock
index 0d77b5a93949320ea48c4457d38f83a5636b1e54..aabd50a8c955d95e42a14d475c7ac9fc011b4dd8 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3507,6 +3507,7 @@ dependencies = [
  "fs",
  "futures 0.3.28",
  "gpui",
+ "isahc",
  "language",
  "log",
  "lsp",
diff --git a/crates/extension/Cargo.toml b/crates/extension/Cargo.toml
index df02174e1e410301df2efdd9a7ef3299d96036af..7d6713729af3087d6becb66c7fdc2db4e5f73866 100644
--- a/crates/extension/Cargo.toml
+++ b/crates/extension/Cargo.toml
@@ -23,6 +23,7 @@ collections.workspace = true
 fs.workspace = true
 futures.workspace = true
 gpui.workspace = true
+isahc.workspace = true
 language.workspace = true
 log.workspace = true
 lsp.workspace = true
diff --git a/crates/extension/src/extension_store.rs b/crates/extension/src/extension_store.rs
index 72001a0f73eaef040dcb6ace3ccc2a4af8eeb918..d2cfe660dbaf5058649c2c5e341a03e94bf71049 100644
--- a/crates/extension/src/extension_store.rs
+++ b/crates/extension/src/extension_store.rs
@@ -605,7 +605,23 @@ impl ExtensionStore {
             )
             .await?;
 
-            let decompressed_bytes = GzipDecoder::new(BufReader::new(response.body_mut()));
+            let content_length = response
+                .headers()
+                .get(isahc::http::header::CONTENT_LENGTH)
+                .and_then(|value| value.to_str().ok()?.parse::<usize>().ok());
+
+            let mut body = BufReader::new(response.body_mut());
+            let mut tgz_bytes = Vec::new();
+            body.read_to_end(&mut tgz_bytes).await?;
+
+            if let Some(content_length) = content_length {
+                let actual_len = tgz_bytes.len();
+                if content_length != actual_len {
+                    bail!("downloaded extension size {actual_len} does not match content length {content_length}");
+                }
+            }
+            let decompressed_bytes = GzipDecoder::new(BufReader::new(tgz_bytes.as_slice()));
+            // let decompressed_bytes = GzipDecoder::new(BufReader::new(tgz_bytes));
             let archive = Archive::new(decompressed_bytes);
             archive.unpack(extension_dir).await?;
             this.update(&mut cx, |this, cx| {