diff --git a/CHANGELOG b/CHANGELOG
index 5931689e59..c80d47f2b0 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -11,6 +11,8 @@ git-annex (10.20241032) UNRELEASED; urgency=medium
     (Needs aws-0.24.3)
   * S3: Send git-annex or other configured User-Agent.
     (Needs aws-0.24.3)
+  * S3: Fix infinite loop and memory blowup when importing from an
+    unversioned S3 bucket that is large enough to need pagination.
 
  -- Joey Hess <id@joeyh.name>  Mon, 11 Nov 2024 12:26:00 -0400
 
diff --git a/Remote/S3.hs b/Remote/S3.hs
index b7d13f11f5..299f7d7644 100644
--- a/Remote/S3.hs
+++ b/Remote/S3.hs
@@ -589,14 +589,23 @@ listImportableContentsS3 hv r info c =
 			continuelistunversioned h [] rsp
 
 	continuelistunversioned h l rsp
-		| S3.gbrIsTruncated rsp = do
-			rsp' <- sendS3Handle h $
-				(S3.getBucket (bucket info))
-					{ S3.gbMarker = S3.gbrNextMarker rsp
-					, S3.gbPrefix = fileprefix
-					}
-			continuelistunversioned h (rsp:l) rsp'
-		| otherwise = return $
+		| S3.gbrIsTruncated rsp =
+			let marker = 
+				S3.gbrNextMarker rsp
+					<|>
+				(S3.objectKey <$> lastMaybe (S3.gbrContents rsp))
+			in case marker of
+				Just _ -> do
+					rsp' <- sendS3Handle h $
+						(S3.getBucket (bucket info))
+							{ S3.gbMarker = marker
+							, S3.gbPrefix = fileprefix
+							}
+					continuelistunversioned h (rsp:l) rsp'
+				Nothing -> nomore
+		| otherwise = nomore
+	  where
+		nomore = return $
 			mkImportableContentsUnversioned info (reverse (rsp:l))
 	
 	continuelistversioned h l rsp