diff --git a/frontend/obsidian-plugin/package.json b/frontend/obsidian-plugin/package.json
index f8d510eb..3cd52514 100644
--- a/frontend/obsidian-plugin/package.json
+++ b/frontend/obsidian-plugin/package.json
@@ -20,7 +20,7 @@
         "fs-extra": "^11.3.2",
         "mini-css-extract-plugin": "^2.9.4",
         "obsidian": "1.11.0",
-        "reconcile-text": "^0.11.0",
+        "reconcile-text": "^0.12.1",
         "resolve-url-loader": "^5.0.0",
         "sass": "^1.96.0",
         "sass-loader": "^16.0.6",
diff --git a/frontend/package-lock.json b/frontend/package-lock.json
index 5aa0bee9..35dec132 100644
--- a/frontend/package-lock.json
+++ b/frontend/package-lock.json
@@ -5954,9 +5954,9 @@
             }
         },
         "node_modules/reconcile-text": {
-            "version": "0.8.0",
-            "resolved": "https://registry.npmjs.org/reconcile-text/-/reconcile-text-0.8.0.tgz",
-            "integrity": "sha512-evskVha3YgpP2ZelsFxP9t7CuKnwE7TrsH3FdrH2mfKbzjUWiNF7scHXsFbFS921lmFlAOB94DHNAWPvL34Mqg==",
+            "version": "0.12.1",
+            "resolved": "https://registry.npmjs.org/reconcile-text/-/reconcile-text-0.12.1.tgz",
+            "integrity": "sha512-UtDykRp8k/hDhMMqcexkeCmGCFy/ScrKFYkIj2lpT7OYEN5eXL6BeUORgf9jPZ+sMf6/z5tZWSOC1Q87jNzhUQ==",
             "dev": true,
             "license": "MIT"
         },
@@ -7686,7 +7686,7 @@
                 "fs-extra": "^11.3.2",
                 "mini-css-extract-plugin": "^2.9.4",
                 "obsidian": "1.11.0",
-                "reconcile-text": "^0.11.0",
+                "reconcile-text": "^0.12.1",
                 "resolve-url-loader": "^5.0.0",
                 "sass": "^1.96.0",
                 "sass-loader": "^16.0.6",
@@ -7740,13 +7740,6 @@
                 "@codemirror/view": "6.38.6"
             }
         },
-        "obsidian-plugin/node_modules/reconcile-text": {
-            "version": "0.11.0",
-            "resolved": "https://registry.npmjs.org/reconcile-text/-/reconcile-text-0.11.0.tgz",
-            "integrity": "sha512-a3sy3obazoc1BMEHx6IQn8ESZKnakVWZuRLi7OSEB56E8evRtrXBMj7yuo10fMoG4JkcZC6tokOfzpwZAKX+PQ==",
-            "dev": true,
-            "license": "MIT"
-        },
         "obsidian-plugin/node_modules/typescript": {
             "version": "5.9.3",
             "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.9.3.tgz",
@@ -7775,7 +7768,7 @@
                 "@types/node": "^24.8.1",
                 "byte-base64": "^1.1.0",
                 "minimatch": "^10.0.1",
-                "reconcile-text": "^0.8.0",
+                "reconcile-text": "^0.12.1",
                 "ts-loader": "^9.5.2",
                 "tslib": "2.8.1",
                 "tsx": "^4.20.6",
diff --git a/frontend/sync-client/package.json b/frontend/sync-client/package.json
index 19ddd759..45f26acf 100644
--- a/frontend/sync-client/package.json
+++ b/frontend/sync-client/package.json
@@ -17,7 +17,7 @@
     "devDependencies": {
         "byte-base64": "^1.1.0",
         "minimatch": "^10.0.1",
-        "reconcile-text": "^0.8.0",
+        "reconcile-text": "^0.12.1",
         "uuid": "^13.0.0",
         "@types/node": "^24.8.1",
         "ts-loader": "^9.5.2",
diff --git a/frontend/test-support/file-application.test.ts b/frontend/test-support/file-application.test.ts
index 6b99147c..3d140620 100644
--- a/frontend/test-support/file-application.test.ts
+++ b/frontend/test-support/file-application.test.ts
@@ -89,6 +89,49 @@ test("content edited after planning is merged with the incoming snapshot", async
     );
 });
 
+test("repeated large text replacements reuse WebAssembly memory", async () => {
+    // The replacement from fuzz-193329 exhausted reconcile-text 0.8.0's
+    // allocator over repeated merges, eventually stalling sync and trapping.
+    const original = (
+        " مرحباéשלום\t日本語\ncaféalphaalphaनमस्ते🦊🌍café\n" +
+        "🌍مرحبامرحباनमस्तेשלום\talphaalphacaféمرحبا🌍\r\n日本語مرحبا"
+    ).repeat(128);
+    const replacement = await hashSnapshot({
+        content: bytes(
+            (
+                "alpha🌍éनमस्ते日本語שלום\uFEFFשלום\t\r\n" +
+                "\uFEFF🦊 🦊🌍नमस्ते\uFEFFéمرحبا\r\ncafé🌍é🌍"
+            ).repeat(128)
+        )
+    });
+    const f = await fixture({ "a.md": original });
+    const expected = (await f.files.readSnapshot("a.md"))!;
+    const apply = async () => {
+        await f.disk.userWrite("a.md", bytes(original));
+        await f.files.applyChanges(structuredClone(f.database.state), {
+            a: { expected, replacement }
+        });
+        assert.deepEqual(f.disk.userFiles().get("a.md"), replacement.content);
+        assert.equal(
+            f.database.state.documents.a.observedHash,
+            replacement.hash
+        );
+    };
+
+    await apply(); // Warm up the module and its allocator before measuring.
+    const warmedMemory = process.memoryUsage.rss();
+    for (let repeat = 0; repeat < 4; repeat++) {
+        await apply();
+        // Measure resident memory because V8's external counter can omit WASM
+        // memory after GC. The old allocator grew ~150 MiB on every call.
+        const growth = process.memoryUsage.rss() - warmedMemory;
+        assert(
+            growth < 64 * 1024 * 1024,
+            `Resident memory grew by ${growth} bytes`
+        );
+    }
+});
+
 test("deleting the source after planning does not resurrect it", async () => {
     const f = await fixture();
     const next = structuredClone(f.database.state);