diff --git a/pkgs/development/web/nodejs/v18.nix b/pkgs/development/web/nodejs/v18.nix
index 1ab63eac7951..b9a50c718cb2 100644
--- a/pkgs/development/web/nodejs/v18.nix
+++ b/pkgs/development/web/nodejs/v18.nix
@@ -54,5 +54,20 @@ buildNodejs {
       stripLen = 1;
       hash = "sha256-WVxsoEcJu0WBTyelNrVQFTZxJhnekQb1GrueeRBRdnY=";
     })
+    # Backport V8 fixes for LLVM 19.
+    (fetchpatch2 {
+      url = "https://chromium.googlesource.com/v8/v8/+/182d9c05e78b1ddb1cb8242cd3628a7855a0336f%5E%21/?format=TEXT";
+      decode = "base64 -d";
+      extraPrefix = "deps/v8/";
+      stripLen = 1;
+      hash = "sha256-bDTwFbATPn5W4VifWz/SqaiigXYDWHq785C64VezuUE=";
+    })
+    (fetchpatch2 {
+      url = "https://chromium.googlesource.com/v8/v8/+/1a3ecc2483b2dba6ab9f7e9f8f4b60dbfef504b7%5E%21/?format=TEXT";
+      decode = "base64 -d";
+      extraPrefix = "deps/v8/";
+      stripLen = 1;
+      hash = "sha256-6y3aEqxNC4iTQEv1oewodJrhOHxjp5xZMq1P1QL94Rg=";
+    })
   ] ++ gypPatches;
 }
diff --git a/pkgs/development/web/nodejs/v20.nix b/pkgs/development/web/nodejs/v20.nix
index 9f0e1cc38b88..b147771e6660 100644
--- a/pkgs/development/web/nodejs/v20.nix
+++ b/pkgs/development/web/nodejs/v20.nix
@@ -55,5 +55,20 @@ buildNodejs {
       stripLen = 1;
       hash = "sha256-WVxsoEcJu0WBTyelNrVQFTZxJhnekQb1GrueeRBRdnY=";
     })
+    # Backport V8 fixes for LLVM 19.
+    (fetchpatch2 {
+      url = "https://chromium.googlesource.com/v8/v8/+/182d9c05e78b1ddb1cb8242cd3628a7855a0336f%5E%21/?format=TEXT";
+      decode = "base64 -d";
+      extraPrefix = "deps/v8/";
+      stripLen = 1;
+      hash = "sha256-bDTwFbATPn5W4VifWz/SqaiigXYDWHq785C64VezuUE=";
+    })
+    (fetchpatch2 {
+      url = "https://chromium.googlesource.com/v8/v8/+/1a3ecc2483b2dba6ab9f7e9f8f4b60dbfef504b7%5E%21/?format=TEXT";
+      decode = "base64 -d";
+      extraPrefix = "deps/v8/";
+      stripLen = 1;
+      hash = "sha256-6y3aEqxNC4iTQEv1oewodJrhOHxjp5xZMq1P1QL94Rg=";
+    })
   ] ++ gypPatches;
 }