diff --git a/src/Sql/Vault/dbo/Stored Procedures/Cipher/CipherDetails_Update.sql b/src/Sql/Vault/dbo/Stored Procedures/Cipher/CipherDetails_Update.sql
index 8fc95eb302..214b74d092 100644
--- a/src/Sql/Vault/dbo/Stored Procedures/Cipher/CipherDetails_Update.sql	
+++ b/src/Sql/Vault/dbo/Stored Procedures/Cipher/CipherDetails_Update.sql	
@@ -6,7 +6,7 @@
     @Data NVARCHAR(MAX),
     @Favorites NVARCHAR(MAX), -- not used
     @Folders NVARCHAR(MAX), -- not used
-    @Attachments NVARCHAR(MAX),
+    @Attachments NVARCHAR(MAX), -- not used
     @CreationDate DATETIME2(7),
     @RevisionDate DATETIME2(7),
     @FolderId UNIQUEIDENTIFIER,
@@ -50,7 +50,6 @@ BEGIN
             ELSE
                 JSON_MODIFY([Favorites], @UserIdPath, NULL)
             END,
-        [Attachments] = @Attachments,
         [Reprompt] = @Reprompt,
         [CreationDate] = @CreationDate,
         [RevisionDate] = @RevisionDate,
diff --git a/src/Sql/Vault/dbo/Stored Procedures/Cipher/Cipher_Create.sql b/src/Sql/Vault/dbo/Stored Procedures/Cipher/Cipher_Create.sql
index c03c27ea78..676c013cc8 100644
--- a/src/Sql/Vault/dbo/Stored Procedures/Cipher/Cipher_Create.sql	
+++ b/src/Sql/Vault/dbo/Stored Procedures/Cipher/Cipher_Create.sql	
@@ -6,7 +6,7 @@
     @Data NVARCHAR(MAX),
     @Favorites NVARCHAR(MAX),
     @Folders NVARCHAR(MAX),
-    @Attachments NVARCHAR(MAX),
+    @Attachments NVARCHAR(MAX), -- not used
     @CreationDate DATETIME2(7),
     @RevisionDate DATETIME2(7),
     @DeletedDate DATETIME2(7),
@@ -25,7 +25,6 @@ BEGIN
         [Data],
         [Favorites],
         [Folders],
-        [Attachments],
         [CreationDate],
         [RevisionDate],
         [DeletedDate],
@@ -41,7 +40,6 @@ BEGIN
         @Data,
         @Favorites,
         @Folders,
-        @Attachments,
         @CreationDate,
         @RevisionDate,
         @DeletedDate,
diff --git a/src/Sql/Vault/dbo/Stored Procedures/Cipher/Cipher_DeleteAttachment.sql b/src/Sql/Vault/dbo/Stored Procedures/Cipher/Cipher_DeleteAttachment.sql
index 5983f557c2..75a0468b42 100644
--- a/src/Sql/Vault/dbo/Stored Procedures/Cipher/Cipher_DeleteAttachment.sql	
+++ b/src/Sql/Vault/dbo/Stored Procedures/Cipher/Cipher_DeleteAttachment.sql	
@@ -10,20 +10,59 @@ BEGIN
 
     DECLARE @UserId UNIQUEIDENTIFIER
     DECLARE @OrganizationId UNIQUEIDENTIFIER
+    DECLARE @CurrentAttachments NVARCHAR(MAX)
+    DECLARE @NewAttachments NVARCHAR(MAX)
 
+    -- Get current cipher data
     SELECT
         @UserId = [UserId],
-        @OrganizationId = [OrganizationId]
-    FROM 
+        @OrganizationId = [OrganizationId],
+        @CurrentAttachments = [Attachments]
+    FROM
         [dbo].[Cipher]
     WHERE [Id] = @Id
 
-    UPDATE
-        [dbo].[Cipher]
-    SET
-        [Attachments] = JSON_MODIFY([Attachments], @AttachmentIdPath, NULL)
-    WHERE
-        [Id] = @Id
+    -- If there are no attachments, nothing to do
+    IF @CurrentAttachments IS NULL
+    BEGIN
+        RETURN;
+    END
+
+    -- Validate the initial JSON
+    IF ISJSON(@CurrentAttachments) = 0
+    BEGIN
+        THROW 50000, 'Current initial attachments data is not valid JSON', 1;
+        RETURN;
+    END
+
+    -- Check if the attachment exists before trying to remove it
+    IF JSON_PATH_EXISTS(@CurrentAttachments, @AttachmentIdPath) = 0
+    BEGIN
+        -- Attachment doesn't exist, nothing to do
+        RETURN;
+    END
+
+    -- Create the new attachments JSON with the specified attachment removed
+    SET @NewAttachments = JSON_MODIFY(@CurrentAttachments, @AttachmentIdPath, NULL)
+
+    -- Validate the resulting JSON
+    IF ISJSON(@NewAttachments) = 0
+    BEGIN
+        THROW 50000, 'Failed to create valid JSON when removing attachment', 1;
+        RETURN;
+    END
+
+    -- Check if we've removed all attachments and have an empty object
+    IF @NewAttachments = '{}'
+    BEGIN
+        -- If we have an empty JSON object, set to NULL instead
+        SET @NewAttachments = NULL;
+    END
+
+    -- Update with validated JSON
+    UPDATE [dbo].[Cipher]
+    SET [Attachments] = @NewAttachments
+    WHERE [Id] = @Id
 
     IF @OrganizationId IS NOT NULL
     BEGIN
diff --git a/src/Sql/Vault/dbo/Stored Procedures/Cipher/Cipher_Update.sql b/src/Sql/Vault/dbo/Stored Procedures/Cipher/Cipher_Update.sql
index 7815aa3053..0aa73ae9b6 100644
--- a/src/Sql/Vault/dbo/Stored Procedures/Cipher/Cipher_Update.sql	
+++ b/src/Sql/Vault/dbo/Stored Procedures/Cipher/Cipher_Update.sql	
@@ -6,7 +6,7 @@
     @Data NVARCHAR(MAX),
     @Favorites NVARCHAR(MAX),
     @Folders NVARCHAR(MAX),
-    @Attachments NVARCHAR(MAX),
+    @Attachments NVARCHAR(MAX), -- not used
     @CreationDate DATETIME2(7),
     @RevisionDate DATETIME2(7),
     @DeletedDate DATETIME2(7),
@@ -25,7 +25,6 @@ BEGIN
         [Data] = @Data,
         [Favorites] = @Favorites,
         [Folders] = @Folders,
-        [Attachments] = @Attachments,
         [CreationDate] = @CreationDate,
         [RevisionDate] = @RevisionDate,
         [DeletedDate] = @DeletedDate,
@@ -42,4 +41,4 @@ BEGIN
     BEGIN
         EXEC [dbo].[User_BumpAccountRevisionDate] @UserId
     END
-END
\ No newline at end of file
+END
diff --git a/src/Sql/Vault/dbo/Stored Procedures/Cipher/Cipher_UpdateAttachment.sql b/src/Sql/Vault/dbo/Stored Procedures/Cipher/Cipher_UpdateAttachment.sql
index 520df72505..4401a4a0c6 100644
--- a/src/Sql/Vault/dbo/Stored Procedures/Cipher/Cipher_UpdateAttachment.sql	
+++ b/src/Sql/Vault/dbo/Stored Procedures/Cipher/Cipher_UpdateAttachment.sql	
@@ -8,21 +8,75 @@ AS
 BEGIN
     SET NOCOUNT ON
 
+    -- Validate that AttachmentData is valid JSON
+    IF ISJSON(@AttachmentData) = 0
+    BEGIN
+        THROW 50000, 'Invalid JSON format in AttachmentData parameter', 1;
+        RETURN;
+    END
+
+    -- Validate that AttachmentData has the expected structure
+    -- Check for required fields
+    IF JSON_VALUE(@AttachmentData, '$.FileName') IS NULL OR
+       JSON_VALUE(@AttachmentData, '$.Size') IS NULL
+    BEGIN
+        THROW 50000, 'AttachmentData is missing required fields (FileName, Size)', 1;
+        RETURN;
+    END
+
+    -- Validate data types for critical fields
+    DECLARE @Size BIGINT = TRY_CAST(JSON_VALUE(@AttachmentData, '$.Size') AS BIGINT)
+    IF @Size IS NULL OR @Size <= 0
+    BEGIN
+        THROW 50000, 'AttachmentData has invalid Size value', 1;
+        RETURN;
+    END
+
     DECLARE @AttachmentIdKey VARCHAR(50) = CONCAT('"', @AttachmentId, '"')
     DECLARE @AttachmentIdPath VARCHAR(50) = CONCAT('$.', @AttachmentIdKey)
+    DECLARE @NewAttachments NVARCHAR(MAX)
 
-    UPDATE
-        [dbo].[Cipher]
-    SET
-        [Attachments] = 
-            CASE
-            WHEN [Attachments] IS NULL THEN
-                CONCAT('{', @AttachmentIdKey, ':', @AttachmentData, '}')
-            ELSE
-                JSON_MODIFY([Attachments], @AttachmentIdPath, JSON_QUERY(@AttachmentData, '$'))
-            END
-    WHERE
-        [Id] = @Id
+    -- Get current attachments
+    DECLARE @CurrentAttachments NVARCHAR(MAX)
+    SELECT @CurrentAttachments = [Attachments] FROM [dbo].[Cipher] WHERE [Id] = @Id
+
+    -- Prepare the new attachments value based on current state
+    IF @CurrentAttachments IS NULL
+    BEGIN
+        -- Create new JSON object with the attachment
+        SET @NewAttachments = CONCAT('{', @AttachmentIdKey, ':', @AttachmentData, '}')
+
+        -- Validate the constructed JSON
+        IF ISJSON(@NewAttachments) = 0
+        BEGIN
+            THROW 50000, 'Failed to create valid JSON when adding new attachment', 1;
+            RETURN;
+        END
+    END
+    ELSE
+    BEGIN
+        -- Validate existing attachments
+        IF ISJSON(@CurrentAttachments) = 0
+        BEGIN
+            THROW 50000, 'Current attachments data is not valid JSON', 1;
+            RETURN;
+        END
+
+        -- Modify existing JSON
+        SET @NewAttachments = JSON_MODIFY(@CurrentAttachments, @AttachmentIdPath, JSON_QUERY(@AttachmentData, '$'))
+
+        -- Validate the modified JSON
+        IF ISJSON(@NewAttachments) = 0
+        BEGIN
+            THROW 50000, 'Failed to create valid JSON when updating existing attachments', 1;
+            RETURN;
+        END
+    END
+
+    -- Update with validated JSON
+    UPDATE [dbo].[Cipher]
+    SET [Attachments] = @NewAttachments
+    WHERE [Id] = @Id
 
     IF @OrganizationId IS NOT NULL
     BEGIN
@@ -34,4 +88,4 @@ BEGIN
         EXEC [dbo].[User_UpdateStorage] @UserId
         EXEC [dbo].[User_BumpAccountRevisionDate] @UserId
     END
-END
\ No newline at end of file
+END
diff --git a/util/Migrator/DbScripts/2025-04-16_00_AttachmentJsonValidation.sql b/util/Migrator/DbScripts/2025-04-16_00_AttachmentJsonValidation.sql
new file mode 100644
index 0000000000..a501b28574
--- /dev/null
+++ b/util/Migrator/DbScripts/2025-04-16_00_AttachmentJsonValidation.sql
@@ -0,0 +1,350 @@
+CREATE OR ALTER PROCEDURE [dbo].[Cipher_UpdateAttachment]
+    @Id UNIQUEIDENTIFIER,
+    @UserId UNIQUEIDENTIFIER,
+    @OrganizationId UNIQUEIDENTIFIER,
+    @AttachmentId VARCHAR(50),
+    @AttachmentData NVARCHAR(MAX)
+AS
+BEGIN
+    SET NOCOUNT ON
+
+    -- Validate that AttachmentData is valid JSON
+    IF ISJSON(@AttachmentData) = 0
+    BEGIN
+        THROW 50000, 'Invalid JSON format in AttachmentData parameter', 1;
+        RETURN;
+    END
+
+    -- Validate that AttachmentData has the expected structure
+    -- Check for required fields
+    IF JSON_VALUE(@AttachmentData, '$.FileName') IS NULL OR
+       JSON_VALUE(@AttachmentData, '$.Size') IS NULL
+    BEGIN
+        THROW 50000, 'AttachmentData is missing required fields (FileName, Size)', 1;
+        RETURN;
+    END
+
+    -- Validate data types for critical fields
+    DECLARE @Size BIGINT = TRY_CAST(JSON_VALUE(@AttachmentData, '$.Size') AS BIGINT)
+    IF @Size IS NULL OR @Size <= 0
+    BEGIN
+        THROW 50000, 'AttachmentData has invalid Size value', 1;
+        RETURN;
+    END
+
+    DECLARE @AttachmentIdKey VARCHAR(50) = CONCAT('"', @AttachmentId, '"')
+    DECLARE @AttachmentIdPath VARCHAR(50) = CONCAT('$.', @AttachmentIdKey)
+    DECLARE @NewAttachments NVARCHAR(MAX)
+
+    -- Get current attachments
+    DECLARE @CurrentAttachments NVARCHAR(MAX)
+    SELECT @CurrentAttachments = [Attachments] FROM [dbo].[Cipher] WHERE [Id] = @Id
+
+    -- Prepare the new attachments value based on current state
+    IF @CurrentAttachments IS NULL
+    BEGIN
+        -- Create new JSON object with the attachment
+        SET @NewAttachments = CONCAT('{', @AttachmentIdKey, ':', @AttachmentData, '}')
+
+        -- Validate the constructed JSON
+        IF ISJSON(@NewAttachments) = 0
+        BEGIN
+            THROW 50000, 'Failed to create valid JSON when adding new attachment', 1;
+            RETURN;
+        END
+    END
+    ELSE
+    BEGIN
+        -- Validate existing attachments
+        IF ISJSON(@CurrentAttachments) = 0
+        BEGIN
+            THROW 50000, 'Current attachments data is not valid JSON', 1;
+            RETURN;
+        END
+
+        -- Modify existing JSON
+        SET @NewAttachments = JSON_MODIFY(@CurrentAttachments, @AttachmentIdPath, JSON_QUERY(@AttachmentData, '$'))
+
+        -- Validate the modified JSON
+        IF ISJSON(@NewAttachments) = 0
+        BEGIN
+            THROW 50000, 'Failed to create valid JSON when updating existing attachments', 1;
+            RETURN;
+        END
+    END
+
+    -- Update with validated JSON
+    UPDATE [dbo].[Cipher]
+    SET [Attachments] = @NewAttachments
+    WHERE [Id] = @Id
+
+    IF @OrganizationId IS NOT NULL
+    BEGIN
+        EXEC [dbo].[Organization_UpdateStorage] @OrganizationId
+        EXEC [dbo].[User_BumpAccountRevisionDateByCipherId] @Id, @OrganizationId
+    END
+    ELSE IF @UserId IS NOT NULL
+    BEGIN
+        EXEC [dbo].[User_UpdateStorage] @UserId
+        EXEC [dbo].[User_BumpAccountRevisionDate] @UserId
+    END
+END
+GO
+
+CREATE OR ALTER PROCEDURE [dbo].[Cipher_DeleteAttachment]
+    @Id UNIQUEIDENTIFIER,
+    @AttachmentId VARCHAR(50)
+AS
+BEGIN
+    SET NOCOUNT ON
+
+    DECLARE @AttachmentIdKey VARCHAR(50) = CONCAT('"', @AttachmentId, '"')
+    DECLARE @AttachmentIdPath VARCHAR(50) = CONCAT('$.', @AttachmentIdKey)
+
+    DECLARE @UserId UNIQUEIDENTIFIER
+    DECLARE @OrganizationId UNIQUEIDENTIFIER
+    DECLARE @CurrentAttachments NVARCHAR(MAX)
+    DECLARE @NewAttachments NVARCHAR(MAX)
+
+    -- Get current cipher data
+    SELECT
+        @UserId = [UserId],
+        @OrganizationId = [OrganizationId],
+        @CurrentAttachments = [Attachments]
+    FROM
+        [dbo].[Cipher]
+    WHERE [Id] = @Id
+
+    -- If there are no attachments, nothing to do
+    IF @CurrentAttachments IS NULL
+    BEGIN
+        RETURN;
+    END
+
+    -- Validate the initial JSON
+    IF ISJSON(@CurrentAttachments) = 0
+    BEGIN
+        THROW 50000, 'Current initial attachments data is not valid JSON', 1;
+        RETURN;
+    END
+
+    -- Check if the attachment exists before trying to remove it
+    IF JSON_PATH_EXISTS(@CurrentAttachments, @AttachmentIdPath) = 0
+    BEGIN
+        -- Attachment doesn't exist, nothing to do
+        RETURN;
+    END
+
+    -- Create the new attachments JSON with the specified attachment removed
+    SET @NewAttachments = JSON_MODIFY(@CurrentAttachments, @AttachmentIdPath, NULL)
+
+    -- Validate the resulting JSON
+    IF ISJSON(@NewAttachments) = 0
+    BEGIN
+        THROW 50000, 'Failed to create valid JSON when removing attachment', 1;
+        RETURN;
+    END
+
+    -- Check if we've removed all attachments and have an empty object
+    IF @NewAttachments = '{}'
+    BEGIN
+        -- If we have an empty JSON object, set to NULL instead
+        SET @NewAttachments = NULL;
+    END
+
+    -- Update with validated JSON
+    UPDATE [dbo].[Cipher]
+    SET [Attachments] = @NewAttachments
+    WHERE [Id] = @Id
+
+    IF @OrganizationId IS NOT NULL
+    BEGIN
+        EXEC [dbo].[Organization_UpdateStorage] @OrganizationId
+        EXEC [dbo].[User_BumpAccountRevisionDateByCipherId] @Id, @OrganizationId
+    END
+    ELSE IF @UserId IS NOT NULL
+    BEGIN
+        EXEC [dbo].[User_UpdateStorage] @UserId
+        EXEC [dbo].[User_BumpAccountRevisionDate] @UserId
+    END
+END
+GO
+
+-- Remove [Attachments] assignment from Cipher_Create, Cipher_Update, and CipherDetails_Update procedures
+
+CREATE OR ALTER PROCEDURE [dbo].[Cipher_Create]
+    @Id UNIQUEIDENTIFIER OUTPUT,
+    @UserId UNIQUEIDENTIFIER,
+    @OrganizationId UNIQUEIDENTIFIER,
+    @Type TINYINT,
+    @Data NVARCHAR(MAX),
+    @Favorites NVARCHAR(MAX),
+    @Folders NVARCHAR(MAX),
+    @Attachments NVARCHAR(MAX), -- not used
+    @CreationDate DATETIME2(7),
+    @RevisionDate DATETIME2(7),
+    @DeletedDate DATETIME2(7),
+    @Reprompt TINYINT,
+    @Key VARCHAR(MAX) = NULL
+AS
+BEGIN
+    SET NOCOUNT ON
+
+    INSERT INTO [dbo].[Cipher]
+    (
+        [Id],
+        [UserId],
+        [OrganizationId],
+        [Type],
+        [Data],
+        [Favorites],
+        [Folders],
+        [CreationDate],
+        [RevisionDate],
+        [DeletedDate],
+        [Reprompt],
+        [Key]
+    )
+    VALUES
+    (
+        @Id,
+        CASE WHEN @OrganizationId IS NULL THEN @UserId ELSE NULL END,
+        @OrganizationId,
+        @Type,
+        @Data,
+        @Favorites,
+        @Folders,
+        @CreationDate,
+        @RevisionDate,
+        @DeletedDate,
+        @Reprompt,
+        @Key
+    )
+
+    IF @OrganizationId IS NOT NULL
+    BEGIN
+        EXEC [dbo].[User_BumpAccountRevisionDateByCipherId] @Id, @OrganizationId
+    END
+    ELSE IF @UserId IS NOT NULL
+    BEGIN
+        EXEC [dbo].[User_BumpAccountRevisionDate] @UserId
+    END
+END
+GO
+
+CREATE OR ALTER PROCEDURE [dbo].[CipherDetails_Update]
+    @Id UNIQUEIDENTIFIER,
+    @UserId UNIQUEIDENTIFIER,
+    @OrganizationId UNIQUEIDENTIFIER,
+    @Type TINYINT,
+    @Data NVARCHAR(MAX),
+    @Favorites NVARCHAR(MAX), -- not used
+    @Folders NVARCHAR(MAX), -- not used
+    @Attachments NVARCHAR(MAX), -- not used
+    @CreationDate DATETIME2(7),
+    @RevisionDate DATETIME2(7),
+    @FolderId UNIQUEIDENTIFIER,
+    @Favorite BIT,
+    @Edit BIT, -- not used
+    @ViewPassword BIT, -- not used
+    @Manage BIT, -- not used
+    @OrganizationUseTotp BIT, -- not used
+    @DeletedDate DATETIME2(2),
+    @Reprompt TINYINT,
+    @Key VARCHAR(MAX) = NULL
+AS
+BEGIN
+    SET NOCOUNT ON
+
+    DECLARE @UserIdKey VARCHAR(50) = CONCAT('"', @UserId, '"')
+    DECLARE @UserIdPath VARCHAR(50) = CONCAT('$.', @UserIdKey)
+
+    UPDATE
+        [dbo].[Cipher]
+    SET
+        [UserId] = CASE WHEN @OrganizationId IS NULL THEN @UserId ELSE NULL END,
+        [OrganizationId] = @OrganizationId,
+        [Type] = @Type,
+        [Data] = @Data,
+        [Folders] =
+            CASE
+            WHEN @FolderId IS NOT NULL AND [Folders] IS NULL THEN
+                CONCAT('{', @UserIdKey, ':"', @FolderId, '"', '}')
+            WHEN @FolderId IS NOT NULL THEN
+                JSON_MODIFY([Folders], @UserIdPath, CAST(@FolderId AS VARCHAR(50)))
+            ELSE
+                JSON_MODIFY([Folders], @UserIdPath, NULL)
+            END,
+        [Favorites] =
+            CASE
+            WHEN @Favorite = 1 AND [Favorites] IS NULL THEN
+                CONCAT('{', @UserIdKey, ':true}')
+            WHEN @Favorite = 1 THEN
+                JSON_MODIFY([Favorites], @UserIdPath, CAST(1 AS BIT))
+            ELSE
+                JSON_MODIFY([Favorites], @UserIdPath, NULL)
+            END,
+        [Reprompt] = @Reprompt,
+        [CreationDate] = @CreationDate,
+        [RevisionDate] = @RevisionDate,
+        [DeletedDate] = @DeletedDate,
+        [Key] = @Key
+    WHERE
+        [Id] = @Id
+
+    IF @OrganizationId IS NOT NULL
+    BEGIN
+        EXEC [dbo].[User_BumpAccountRevisionDateByCipherId] @Id, @OrganizationId
+    END
+    ELSE IF @UserId IS NOT NULL
+    BEGIN
+        EXEC [dbo].[User_BumpAccountRevisionDate] @UserId
+    END
+END
+GO
+
+CREATE OR ALTER PROCEDURE [dbo].[Cipher_Update]
+    @Id UNIQUEIDENTIFIER,
+    @UserId UNIQUEIDENTIFIER,
+    @OrganizationId UNIQUEIDENTIFIER,
+    @Type TINYINT,
+    @Data NVARCHAR(MAX),
+    @Favorites NVARCHAR(MAX),
+    @Folders NVARCHAR(MAX),
+    @Attachments NVARCHAR(MAX), -- not used
+    @CreationDate DATETIME2(7),
+    @RevisionDate DATETIME2(7),
+    @DeletedDate DATETIME2(7),
+    @Reprompt TINYINT,
+    @Key VARCHAR(MAX) = NULL
+AS
+BEGIN
+    SET NOCOUNT ON
+
+    UPDATE
+        [dbo].[Cipher]
+    SET
+        [UserId] = CASE WHEN @OrganizationId IS NULL THEN @UserId ELSE NULL END,
+        [OrganizationId] = @OrganizationId,
+        [Type] = @Type,
+        [Data] = @Data,
+        [Favorites] = @Favorites,
+        [Folders] = @Folders,
+        [CreationDate] = @CreationDate,
+        [RevisionDate] = @RevisionDate,
+        [DeletedDate] = @DeletedDate,
+        [Reprompt] = @Reprompt,
+        [Key] = @Key
+    WHERE
+        [Id] = @Id
+
+    IF @OrganizationId IS NOT NULL
+    BEGIN
+        EXEC [dbo].[User_BumpAccountRevisionDateByCipherId] @Id, @OrganizationId
+    END
+    ELSE IF @UserId IS NOT NULL
+    BEGIN
+        EXEC [dbo].[User_BumpAccountRevisionDate] @UserId
+    END
+END
+GO