diff --git a/crates/bitwarden-vault/src/cipher/attachment.rs b/crates/bitwarden-vault/src/cipher/attachment.rs
index e37b6ad02..38ad7d6cd 100644
--- a/crates/bitwarden-vault/src/cipher/attachment.rs
+++ b/crates/bitwarden-vault/src/cipher/attachment.rs
@@ -36,6 +36,18 @@ pub struct AttachmentView {
     pub size_name: Option<String>,
     pub file_name: Option<String>,
     pub key: Option<EncString>,
+    /// The decrypted attachmentkey in base64 format.
+    ///
+    /// **TEMPORARY FIELD**: This field is a temporary workaround to provide
+    /// decrypted attachment keys to the TypeScript client during the migration
+    /// process. It will be removed once the encryption/decryption logic is
+    /// fully migrated to the SDK.
+    ///
+    /// **Ticket**: <https://bitwarden.atlassian.net/browse/PM-23005>
+    ///
+    /// Do not rely on this field for long-term use.
+    #[cfg(feature = "wasm")]
+    pub decrypted_key: Option<String>,
 }
 
 #[allow(missing_docs)]
@@ -160,6 +172,17 @@ impl Decryptable<KeyIds, SymmetricKeyId, AttachmentView> for Attachment {
         ctx: &mut KeyStoreContext<KeyIds>,
         key: SymmetricKeyId,
     ) -> Result<AttachmentView, CryptoError> {
+        let decrypted_key = if let Some(attachment_key) = &self.key {
+            let content_key_id = ctx.unwrap_symmetric_key(key, ATTACHMENT_KEY, attachment_key)?;
+
+            #[allow(deprecated)]
+            let actual_key = ctx.dangerous_get_symmetric_key(content_key_id)?;
+
+            Some(actual_key.to_base64())
+        } else {
+            None
+        };
+
         Ok(AttachmentView {
             id: self.id.clone(),
             url: self.url.clone(),
@@ -167,6 +190,8 @@ impl Decryptable<KeyIds, SymmetricKeyId, AttachmentView> for Attachment {
             size_name: self.size_name.clone(),
             file_name: self.file_name.decrypt(ctx, key)?,
             key: self.key.clone(),
+            #[cfg(feature = "wasm")]
+            decrypted_key,
         })
     }
 }
@@ -223,6 +248,7 @@ mod tests {
             size_name: Some("100 Bytes".into()),
             file_name: Some("Test.txt".into()),
             key: None,
+            decrypted_key: None,
         };
 
         let contents = b"This is a test file that we will encrypt. It's 100 bytes long, the encrypted version will be longer!";
@@ -279,6 +305,7 @@ mod tests {
             size_name: Some("161 Bytes".into()),
             file_name: Some("Test.txt".into()),
             key: Some("2.r288/AOSPiaLFkW07EBGBw==|SAmnnCbOLFjX5lnURvoualOetQwuyPc54PAmHDTRrhT0gwO9ailna9U09q9bmBfI5XrjNNEsuXssgzNygRkezoVQvZQggZddOwHB6KQW5EQ=|erIMUJp8j+aTcmhdE50zEX+ipv/eR1sZ7EwULJm/6DY=".parse().unwrap()),
+            decrypted_key: None,
         };
 
         let cipher  = Cipher {
@@ -336,6 +363,7 @@ mod tests {
             size_name: Some("161 Bytes".into()),
             file_name: Some("Test.txt".into()),
             key: None,
+            decrypted_key: None,
         };
 
         let cipher  = Cipher {
diff --git a/crates/bitwarden-vault/src/cipher/cipher.rs b/crates/bitwarden-vault/src/cipher/cipher.rs
index 0d4c515dd..77754ba99 100644
--- a/crates/bitwarden-vault/src/cipher/cipher.rs
+++ b/crates/bitwarden-vault/src/cipher/cipher.rs
@@ -343,7 +343,7 @@ impl Decryptable<KeyIds, SymmetricKeyId, CipherView> for Cipher {
             permissions: self.permissions,
             view_password: self.view_password,
             local_data: self.local_data.decrypt(ctx, ciphers_key).ok().flatten(),
-            attachments: self.attachments.decrypt(ctx, ciphers_key).ok().flatten(),
+            attachments: self.attachments.decrypt(ctx, ciphers_key)?,
             fields: self.fields.decrypt(ctx, ciphers_key).ok().flatten(),
             password_history: self
                 .password_history
@@ -962,6 +962,7 @@ mod tests {
             size_name: None,
             file_name: Some("Attachment test name".into()),
             key: None,
+            decrypted_key: None,
         };
         cipher.attachments = Some(vec![attachment]);
 
@@ -1031,6 +1032,7 @@ mod tests {
             size_name: None,
             file_name: Some("Attachment test name".into()),
             key: None,
+            decrypted_key: None,
         };
         cipher.attachments = Some(vec![attachment]);
 
@@ -1074,6 +1076,7 @@ mod tests {
             size_name: None,
             file_name: Some("Attachment test name".into()),
             key: Some(attachment_key_enc),
+            decrypted_key: None,
         };
         cipher.attachments = Some(vec![attachment]);
         let cred = generate_fido2(&mut key_store.context(), SymmetricKeyId::User);
@@ -1141,6 +1144,7 @@ mod tests {
             size_name: None,
             file_name: Some("Attachment test name".into()),
             key: Some(attachment_key_enc.clone()),
+            decrypted_key: None,
         };
         cipher.attachments = Some(vec![attachment]);