diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2344a53cc2..154916a31c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## [Unreleased]
 
+- Fix build failures for modules with a vendored `descriptor.proto`.
 - Fix LSP incorrectly reporting "edition '2024' not yet fully supported" errors.
 - Fix CEL compilation error messages in `buf lint` to use the structured error API instead of parsing cel-go's text output.
 
diff --git a/go.mod b/go.mod
index 3e9046418f..a8f5f6ba52 100644
--- a/go.mod
+++ b/go.mod
@@ -18,7 +18,7 @@ require (
 	connectrpc.com/connect v1.19.1
 	connectrpc.com/grpcreflect v1.3.0
 	connectrpc.com/otelconnect v0.9.0
-	github.com/bufbuild/protocompile v0.14.2-0.20260416105908-db11c79f9322
+	github.com/bufbuild/protocompile v0.14.2-0.20260417153234-65c782f91a0b
 	github.com/bufbuild/protoplugin v0.0.0-20260414125817-25d1d281b46b
 	github.com/cli/browser v1.3.0
 	github.com/gofrs/flock v0.13.0
diff --git a/go.sum b/go.sum
index 72196b695a..153f5acfcf 100644
--- a/go.sum
+++ b/go.sum
@@ -42,8 +42,8 @@ github.com/bmatcuk/doublestar/v4 v4.10.0 h1:zU9WiOla1YA122oLM6i4EXvGW62DvKZVxIe6
 github.com/bmatcuk/doublestar/v4 v4.10.0/go.mod h1:xBQ8jztBU6kakFMg+8WGxn0c6z1fTSPVIjEY1Wr7jzc=
 github.com/brianvoe/gofakeit/v6 v6.28.0 h1:Xib46XXuQfmlLS2EXRuJpqcw8St6qSZz75OUo0tgAW4=
 github.com/brianvoe/gofakeit/v6 v6.28.0/go.mod h1:Xj58BMSnFqcn/fAQeSK+/PLtC5kSb7FJIq4JyGa8vEs=
-github.com/bufbuild/protocompile v0.14.2-0.20260416105908-db11c79f9322 h1:0jR8G4rU/roKE9WY0Mh72a0t5GegneOgezPNdzqfI1M=
-github.com/bufbuild/protocompile v0.14.2-0.20260416105908-db11c79f9322/go.mod h1:DhgqsRznX/F0sGkUYtTQJRP+q8xMReQRQ3qr+n1opWU=
+github.com/bufbuild/protocompile v0.14.2-0.20260417153234-65c782f91a0b h1:0q84wQoejn+OL3iUOrOuYrkNfrzwwlcPwDnOhc1ztr8=
+github.com/bufbuild/protocompile v0.14.2-0.20260417153234-65c782f91a0b/go.mod h1:DhgqsRznX/F0sGkUYtTQJRP+q8xMReQRQ3qr+n1opWU=
 github.com/bufbuild/protoplugin v0.0.0-20260414125817-25d1d281b46b h1:b7wvo9ZhjLzCp7tGbOUMvgtYTnd33zGSAmMxcdxMnhQ=
 github.com/bufbuild/protoplugin v0.0.0-20260414125817-25d1d281b46b/go.mod h1:c5D8gWRIZ2HLWO3gXYTtUfw/hbJyD8xikv2ooPxnklQ=
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
diff --git a/private/buf/bufformat/formatter.go b/private/buf/bufformat/formatter.go
index 81804c9d0e..8a36fa6f87 100644
--- a/private/buf/bufformat/formatter.go
+++ b/private/buf/bufformat/formatter.go
@@ -438,16 +438,7 @@ func (f *formatter) writeImport(importNode *ast.ImportNode, forceCompact, first
 	// leading comments.
 	f.writeStartMaybeCompact(importNode.Keyword, forceCompact, first && !f.importHasComment(importNode))
 	f.Space()
-	// We don't want to write the "public" and "weak" nodes
-	// if they aren't defined. One could be set, but never both.
-	switch {
-	case importNode.Public != nil:
-		f.writeInline(importNode.Public)
-		f.Space()
-	case importNode.Weak != nil:
-		f.writeInline(importNode.Weak)
-		f.Space()
-	case importNode.Modifier != nil:
+	if importNode.Modifier != nil {
 		f.writeInline(importNode.Modifier)
 		f.Space()
 	}
@@ -2507,8 +2498,7 @@ func (f *formatter) importHasComment(importNode *ast.ImportNode) bool {
 	return f.nodeHasComment(importNode.Keyword) ||
 		f.nodeHasComment(importNode.Name) ||
 		f.nodeHasComment(importNode.Semicolon) ||
-		f.nodeHasComment(importNode.Public) ||
-		f.nodeHasComment(importNode.Weak)
+		f.nodeHasComment(importNode.Modifier)
 }
 
 func (f *formatter) nodeHasComment(node ast.Node) bool {
@@ -2555,14 +2545,15 @@ func (n infoWithTrailingComments) TrailingComments() ast.Comments {
 // importSortOrder maps import types to a sort order number, so it can be compared and sorted.
 // Higher values sort first: `import`=3, `import public`=2, `import weak`=1.
 func importSortOrder(node *ast.ImportNode) int {
-	switch {
-	case node.Public != nil:
-		return 2
-	case node.Weak != nil:
-		return 1
-	default:
-		return 3
+	if node.Modifier != nil {
+		switch node.Modifier.Val {
+		case "public":
+			return 2
+		case "weak":
+			return 1
+		}
 	}
+	return 3
 }
 
 // isOptionImport reports whether the import has the "option" modifier.
diff --git a/private/buf/buflsp/deprecate.go b/private/buf/buflsp/deprecate.go
index d7e4f7a71b..91d3e7b5cb 100644
--- a/private/buf/buflsp/deprecate.go
+++ b/private/buf/buflsp/deprecate.go
@@ -42,8 +42,8 @@ func (s *server) getDeprecateCodeAction(
 		slog.Uint64("line", uint64(params.Range.Start.Line)),
 		slog.Uint64("char", uint64(params.Range.Start.Character)),
 	)
-	if file.workspace == nil || file.ir == nil || !file.ir.Lowered() {
-		s.logger.DebugContext(ctx, "deprecate: no workspace or valid IR")
+	if file.workspace == nil || file.ir == nil {
+		s.logger.DebugContext(ctx, "deprecate: no workspace or IR")
 		return nil
 	}
 
@@ -62,7 +62,7 @@ func (s *server) getDeprecateCodeAction(
 	checker := newFullNameMatcher(fqnPrefix)
 	edits := make(map[protocol.DocumentURI][]protocol.TextEdit)
 	for _, wsFile := range file.workspace.PathToFile() {
-		if wsFile.ir == nil || !wsFile.ir.Lowered() {
+		if wsFile.ir == nil {
 			continue
 		}
 		fileEdits := generateDeprecationEdits(wsFile, checker)
@@ -191,7 +191,7 @@ func generateDeprecationEdits(file *file, checker *fullNameMatcher) []protocol.T
 
 // getPackageFQN extracts the package FQN components from a file.
 func getPackageFQN(file *file) ir.FullName {
-	if file.ir == nil || !file.ir.Lowered() {
+	if file.ir == nil {
 		return ""
 	}
 	return file.ir.Package()
diff --git a/private/buf/buflsp/file.go b/private/buf/buflsp/file.go
index 038f41dceb..3d19dd510c 100644
--- a/private/buf/buflsp/file.go
+++ b/private/buf/buflsp/file.go
@@ -56,11 +56,8 @@ type file struct {
 	// Version is an opaque version identifier given to us by the LSP client. This
 	// is used in the protocol to disambiguate which version of a file e.g. publishing
 	// diagnostics or symbols an operating refers to.
-	version int32
-	hasText bool // Whether this file has ever had text read into it.
-	// The local path of the descriptor.proto file used for compilation. This is stored for diagnostics.
-	descriptorProtoLocalPath string
-
+	version    int32
+	hasText    bool               // Whether this file has ever had text read into it.
 	workspace  *workspace         // May be nil.
 	objectInfo storage.ObjectInfo // Info in the context of the workspace.
 
@@ -283,10 +280,6 @@ func (f *file) RefreshIR(ctx context.Context) {
 
 	for i, file := range files {
 		file.ir = results[i].Value
-		if file.objectInfo.Path() == "google/protobuf/descriptor.proto" {
-			// Set local path for the descriptor.proto file used for diagnostics.
-			f.descriptorProtoLocalPath = file.objectInfo.LocalPath()
-		}
 		if f != file {
 			// Update symbols for imports.
 			file.IndexSymbols(ctx)
@@ -356,21 +349,6 @@ func (f *file) IndexSymbols(ctx context.Context) {
 		return
 	}
 
-	// The file has not completed lowering, so we cannot continue with symbol indexing here.
-	// To help the user better understand/diagnose this problem, we surface an additional
-	// diagnostic here.
-	if !f.ir.Lowered() {
-		f.diagnostics = append(f.diagnostics, protocol.Diagnostic{
-			Source:   serverName,
-			Severity: protocol.DiagnosticSeverityError,
-			Message: fmt.Sprintf(`The symbols for this file have not been fully resolved due to an invalid version of descriptor.proto located at: %q.
-This is likely due to a vendored descriptor.proto.`,
-				f.descriptorProtoLocalPath,
-			),
-		})
-		return
-	}
-
 	// Throw away all the old symbols and rebuild symbols unconditionally. This is because if
 	// this file depends on a file that has since been modified, we may need to update references.
 	f.symbols = nil
diff --git a/private/buf/buflsp/folding_range.go b/private/buf/buflsp/folding_range.go
index caeefb95e8..df9d471d2f 100644
--- a/private/buf/buflsp/folding_range.go
+++ b/private/buf/buflsp/folding_range.go
@@ -26,7 +26,7 @@ import (
 // foldingRange generates folding ranges for a file.
 // It finds messages, services, enums, and multi-line comment blocks.
 func (s *server) foldingRange(file *file) []protocol.FoldingRange {
-	if file.ir == nil || !file.ir.Lowered() {
+	if file.ir == nil {
 		return nil
 	}
 
diff --git a/private/bufpkg/bufimage/build_image.go b/private/bufpkg/bufimage/build_image.go
index da5ed5a660..0ccee1972f 100644
--- a/private/bufpkg/bufimage/build_image.go
+++ b/private/bufpkg/bufimage/build_image.go
@@ -19,6 +19,7 @@ import (
 	"errors"
 	"fmt"
 	"log/slog"
+	"slices"
 
 	descriptorv1 "buf.build/gen/go/bufbuild/protodescriptor/protocolbuffers/go/buf/descriptor/v1"
 	"buf.build/go/standard/xlog/xslog"
@@ -167,17 +168,6 @@ func compileImage(
 	}
 	irFiles := results[0].Value
 
-	// Validate that all files have completed lowering. If not, then symbols have not been
-	// properly resolved and cannot generate a valid file descriptor set.
-	for _, irFile := range irFiles {
-		if !irFile.Lowered() {
-			return nil, fmt.Errorf(`The symbols for file %q have not been fully resolved due to an invalid version of descriptor.proto, located at %q. This is likely due to a vendored descriptor.proto.`,
-				moduleFileResolver.ExternalPath(irFile.Path()),
-				moduleFileResolver.ExternalPath("google/protobuf/descriptor.proto"),
-			)
-		}
-	}
-
 	fds, resolver, err := irFilesToFileDescriptorSet(irFiles)
 	if err != nil {
 		return nil, err
@@ -257,12 +247,6 @@ func BuildImageFromOpener(
 	}
 	irFiles := results[0].Value
 
-	for _, irFile := range irFiles {
-		if !irFile.Lowered() {
-			logger.WarnContext(ctx, "file not fully lowered", slog.String("path", irFile.Path()))
-		}
-	}
-
 	fds, resolver, err := irFilesToFileDescriptorSet(irFiles)
 	if err != nil {
 		return nil, diagnostics, err
@@ -296,8 +280,21 @@ func irFilesToFileDescriptorSet(irFiles []*ir.File) (*descriptorpb.FileDescripto
 	// Include Buf's descriptor proto alongside the compiled files so that
 	// ReparseExtensions can recognise [descriptorv1.E_BufSourceCodeInfoExtension]
 	// and convert unknown fields to typed extensions.
-	resolverFiles := []*descriptorpb.FileDescriptorProto{
-		protodesc.ToFileDescriptorProto(descriptorv1.File_buf_descriptor_v1_descriptor_proto),
+	//
+	// We only prepend the buf descriptor proto when the compiled files do not already
+	// contain google/protobuf/descriptor.proto. When a vendored descriptor.proto is
+	// present in the compiled output, its FileDescriptorSet definition lacks extension
+	// ranges for the buf extension (field 536000000). protodesc.NewFiles validates
+	// that extension field numbers fall within declared extension ranges when the
+	// containing message is resolved (non-placeholder). Adding the buf descriptor
+	// proto alongside the vendored descriptor.proto causes this validation to fail.
+	var resolverFiles []*descriptorpb.FileDescriptorProto
+	if !slices.ContainsFunc(fds.File, func(file *descriptorpb.FileDescriptorProto) bool {
+		return file.GetName() == "google/protobuf/descriptor.proto"
+	}) {
+		resolverFiles = []*descriptorpb.FileDescriptorProto{
+			protodesc.ToFileDescriptorProto(descriptorv1.File_buf_descriptor_v1_descriptor_proto),
+		}
 	}
 	resolverFiles = append(resolverFiles, fds.File...)
 	resolver := protoencoding.NewLazyResolver(resolverFiles...)