diff --git a/src/RazorSdk/Tasks/FindAssembliesWithReferencesTo.cs b/src/RazorSdk/Tasks/FindAssembliesWithReferencesTo.cs
index 1eba7068e821..0c08fd266380 100644
--- a/src/RazorSdk/Tasks/FindAssembliesWithReferencesTo.cs
+++ b/src/RazorSdk/Tasks/FindAssembliesWithReferencesTo.cs
@@ -9,8 +9,12 @@
 
 namespace Microsoft.AspNetCore.Razor.Tasks
 {
-    public class FindAssembliesWithReferencesTo : Task
+    [MSBuildMultiThreadableTask]
+    public class FindAssembliesWithReferencesTo : Task, IMultiThreadableTask
     {
+        /// <inheritdoc/>
+        public TaskEnvironment TaskEnvironment { get; set; } = TaskEnvironment.Fallback;
+
         [Required]
         public ITaskItem[] TargetAssemblyNames { get; set; }
 
@@ -44,7 +48,7 @@ public override bool Execute()
 
             var targetAssemblyNames = TargetAssemblyNames.Select(s => s.ItemSpec).ToList();
 
-            var provider = new ReferenceResolver((IReadOnlyList<string>)targetAssemblyNames, referenceItems);
+            var provider = new ReferenceResolver((IReadOnlyList<string>)targetAssemblyNames, referenceItems, TaskEnvironment);
             try
             {
                 var assemblyNames = provider.ResolveAssemblies();
diff --git a/src/RazorSdk/Tasks/ReferenceResolver.cs b/src/RazorSdk/Tasks/ReferenceResolver.cs
index 597c43931f68..c0f0357578f3 100644
--- a/src/RazorSdk/Tasks/ReferenceResolver.cs
+++ b/src/RazorSdk/Tasks/ReferenceResolver.cs
@@ -4,6 +4,7 @@
 using System.Diagnostics;
 using System.Reflection.Metadata;
 using System.Reflection.PortableExecutable;
+using Microsoft.Build.Framework;
 
 namespace Microsoft.AspNetCore.Razor.Tasks
 {
@@ -15,9 +16,25 @@ public class ReferenceResolver
         private readonly HashSet<string> _mvcAssemblies;
         private readonly IReadOnlyList<AssemblyItem> _assemblyItems;
         private readonly Dictionary<AssemblyItem, Classification> _classifications;
+        private readonly TaskEnvironment _taskEnvironment = TaskEnvironment.Fallback;
 
-        public ReferenceResolver(IReadOnlyList<string> targetAssemblies, IReadOnlyList<AssemblyItem> assemblyItems)
+        public ReferenceResolver(
+          IReadOnlyList<string> targetAssemblies,
+          IReadOnlyList<AssemblyItem> assemblyItems)
+          : this(targetAssemblies, assemblyItems, null)
         {
+        }
+
+        public ReferenceResolver(
+            IReadOnlyList<string> targetAssemblies,
+            IReadOnlyList<AssemblyItem> assemblyItems,
+            TaskEnvironment? taskEnvironment)
+        {
+            if (taskEnvironment != null)
+            {
+                _taskEnvironment = taskEnvironment;
+            }
+
             _mvcAssemblies = new HashSet<string>(targetAssemblies, StringComparer.Ordinal);
             _assemblyItems = assemblyItems;
             _classifications = new Dictionary<AssemblyItem, Classification>();
@@ -103,12 +120,14 @@ protected virtual IReadOnlyList<AssemblyItem> GetReferences(string file)
         {
             try
             {
-                if (!File.Exists(file))
+                var absoluteFilePath = !String.IsNullOrEmpty(file) ? _taskEnvironment.GetAbsolutePath(file) : file;
+
+                if (!File.Exists(absoluteFilePath))
                 {
                     throw new ReferenceAssemblyNotFoundException(file);
                 }
 
-                using var peReader = new PEReader(File.OpenRead(file));
+                using var peReader = new PEReader(File.OpenRead(absoluteFilePath));
                 if (!peReader.HasMetadata)
                 {
                     return Array.Empty<AssemblyItem>(); // not a managed assembly
diff --git a/test/Microsoft.NET.Sdk.Razor.Tests/FindAssembliesWithReferencesToMultiThreadingTest.cs b/test/Microsoft.NET.Sdk.Razor.Tests/FindAssembliesWithReferencesToMultiThreadingTest.cs
new file mode 100644
index 000000000000..cf8c78416c2c
--- /dev/null
+++ b/test/Microsoft.NET.Sdk.Razor.Tests/FindAssembliesWithReferencesToMultiThreadingTest.cs
@@ -0,0 +1,108 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+#nullable disable
+
+using System.Reflection;
+using Microsoft.AspNetCore.Razor.Tasks;
+using Microsoft.Build.Framework;
+using Moq;
+using TaskItem = Microsoft.Build.Utilities.TaskItem;
+
+namespace Microsoft.NET.Sdk.Razor.Test
+{
+    public class FindAssembliesWithReferencesToMultiThreadingTest
+    {
+        [Fact]
+        public void GetReferences_RelativePath_ResolvesAgainstTaskEnvironmentProjectDirectory()
+        {
+            // The point of the migration: relative paths must be absolutized against
+            // TaskEnvironment.ProjectDirectory instead of the process CWD. The file is placed
+            // in a temp directory distinct from CWD so pre-migration code would not find it.
+            using var temp = new TempDirectory();
+            const string fileName = "stub.dll";
+            File.WriteAllBytes(Path.Combine(temp.Path, fileName), new byte[] { 0 });
+            Directory.GetCurrentDirectory().Should().NotBe(temp.Path,
+                "test must run with CWD distinct from the temp dir so the migration is actually exercised");
+
+            var resolver = CreateExposingResolver(TaskEnvironment.CreateWithProjectDirectoryAndEnvironment(temp.Path));
+
+            resolver.CallGetReferences(fileName).Should().BeEmpty(
+                "the file exists at TaskEnvironment.ProjectDirectory; PEReader's BadImageFormatException is swallowed and an empty list returned");
+        }
+
+
+        [Fact]
+        public void Execute_PassesTaskEnvironmentToResolver_AndResolvesRelativeAssemblyItemSpecs()
+        {
+            // End-to-end wiring test: FindAssembliesWithReferencesTo must forward its
+            // TaskEnvironment to the ReferenceResolver so relative ItemSpecs on Assemblies
+            // are resolved against the project directory, not the process CWD.
+            using var temp = new TempDirectory();
+            const string fileName = "candidate.dll";
+            File.WriteAllBytes(Path.Combine(temp.Path, fileName), new byte[] { 0 });
+
+            var warnings = new List<BuildWarningEventArgs>();
+            var errors = new List<BuildErrorEventArgs>();
+            var buildEngine = new Mock<IBuildEngine>();
+            buildEngine.Setup(e => e.LogWarningEvent(It.IsAny<BuildWarningEventArgs>()))
+                .Callback<BuildWarningEventArgs>(warnings.Add);
+            buildEngine.Setup(e => e.LogErrorEvent(It.IsAny<BuildErrorEventArgs>()))
+                .Callback<BuildErrorEventArgs>(errors.Add);
+
+            var task = new FindAssembliesWithReferencesTo
+            {
+                BuildEngine = buildEngine.Object,
+                TaskEnvironment = TaskEnvironment.CreateWithProjectDirectoryAndEnvironment(temp.Path),
+                TargetAssemblyNames = new ITaskItem[] { new TaskItem("Microsoft.AspNetCore.Mvc") },
+                Assemblies = new ITaskItem[]
+                {
+                    new TaskItem(fileName, new Dictionary<string, string>
+                    {
+                        ["FusionName"] = "Candidate, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null",
+                    }),
+                },
+            };
+
+            task.Execute().Should().BeTrue();
+            errors.Should().BeEmpty();
+            warnings.Should().NotContain(w => w.Code == "RAZORSDK1007",
+                "the file is present under TaskEnvironment.ProjectDirectory; no not-found warning should be raised");
+        }
+
+        private static ExposingReferenceResolver CreateExposingResolver(TaskEnvironment env) =>
+            new(Array.Empty<string>(), Array.Empty<AssemblyItem>(), env);
+
+        private sealed class ExposingReferenceResolver : ReferenceResolver
+        {
+            public ExposingReferenceResolver(
+                IReadOnlyList<string> targetAssemblies,
+                IReadOnlyList<AssemblyItem> assemblyItems,
+                TaskEnvironment taskEnvironment)
+                : base(targetAssemblies, assemblyItems, taskEnvironment)
+            {
+            }
+
+            public IReadOnlyList<AssemblyItem> CallGetReferences(string file) => GetReferences(file);
+        }
+
+        private sealed class TempDirectory : IDisposable
+        {
+            public TempDirectory()
+            {
+                Path = System.IO.Path.Combine(
+                    System.IO.Path.GetTempPath(),
+                    nameof(FindAssembliesWithReferencesToMultiThreadingTest),
+                    Guid.NewGuid().ToString("N"));
+                Directory.CreateDirectory(Path);
+            }
+
+            public string Path { get; }
+
+            public void Dispose()
+            {
+                try { Directory.Delete(Path, recursive: true); } catch { /* best effort */ }
+            }
+        }
+    }
+}