diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,14 @@
 # Changelog
 
+## 0.3
+
+* The semantics of `eitherDecodeV` and `decodeV` have been changed to conform to aeson's `eitherDecode` and `decode`: They now consume until end of input and strip trailing whitespace.
+
+  This is necessary to remove ambiguity when decoding JSON-like values that are
+  not necessarily properly formatted for JSON. For example, parsing a hexadecimal
+  digit sequence that starts with digits but does not have double quotes should
+  fail to parse rather than be interpreted as a number.
+
 #### 0.2.2.1
 
 * Allow `attoparsec 0.12.*`
diff --git a/aeson-utils.cabal b/aeson-utils.cabal
--- a/aeson-utils.cabal
+++ b/aeson-utils.cabal
@@ -1,5 +1,5 @@
 name:                aeson-utils
-version:             0.2.2.1
+version:             0.3
 synopsis:            Utilities for working with Aeson.
 description:         Utilities for working with Aeson.
 license:             BSD3
@@ -27,8 +27,8 @@
   exposed-modules:   Data.Aeson.Utils
   build-depends:
       base == 4.*
-    , aeson >= 0.6 && < 0.8
+    , aeson >= 0.6 && < 0.9
     , attoparsec >= 0.10 && < 0.13
     , bytestring >= 0.9 && < 0.11
     , scientific >= 0.3.2 && < 0.4
-    , text >= 0.11 && < 1.2
+    , text >= 0.11 && < 1.3
diff --git a/src/Data/Aeson/Utils.hs b/src/Data/Aeson/Utils.hs
--- a/src/Data/Aeson/Utils.hs
+++ b/src/Data/Aeson/Utils.hs
@@ -13,12 +13,14 @@
   , floatingOrInteger
   ) where
 
+import Control.Applicative ((<*))
 import Data.Aeson
 import Data.Aeson.Parser (value)
 import Data.Aeson.Types
 import Data.Attoparsec.Lazy (Result (..))
 import Data.Scientific
 import Data.Text (Text)
+import qualified Data.Attoparsec.ByteString.Char8 as Atto (skipSpace)
 import qualified Data.Attoparsec.Lazy as Atto
 import qualified Data.ByteString.Lazy as L
 
@@ -26,7 +28,7 @@
 
 -- | Like 'decodeV', but returns an error message when decoding fails.
 eitherDecodeV :: FromJSON a => L.ByteString -> Either String a
-eitherDecodeV v = case Atto.parse value v of
+eitherDecodeV v = case Atto.parse (value <* Atto.skipSpace <* Atto.endOfInput) v of
   Fail _ _ err -> Left err
   Done _ r     -> case fromJSON r of
     Error e   -> Left e