Ruling on mu’allaq hadeeth
Question

                What is meant by a mu’allaq hadeeth? Are any of them saheeh apart from those that are in al-Bukhaari and Muslim?.
Praise be to Allah.Firstly: 
A mu’aallaq (lit. suspended) hadeeth is one in which one or more narrators are omitted from the beginning of its isnaad by the muhaddith who compiled the book. 
Al-Haafiz ibn Hajar (may Allaah have mercy on him) said in Nuzhat al-Nazr (108-109): 
Among the forms of mu’allaq hadeeths are: 
·Where the entire isnaad is omitted, so it says for example: The Messenger of Allaah (peace and blessings of Allaah be upon him) said…
·Where the entire isnaad is omitted and only the name of the Sahaabi or the names of the Sahaabi and Taabi’i are left.
·Where the name of the one who narrated it is omitted and it is attributed to someone who came above him (in the isnaad). End quote.
Secondly: 
Every hadeeth which is mentioned in the books with the isnaad omitted and which is attributed to the Prophet (peace and blessings of Allaah be upon him), without being attributed to any of the books of Sunnah, is a mu’allaq hadeeth. If the hadeeth has an uninterrupted isnaad (mawsool, lit. connected) in the books of Sunnah, or the compiler who narrated it as a mu’allaq report has given the uninterrupted isnaad elsewhere in his books, then it seems that the one who quoted it as a mu’allaaq report did so only for the sake of brevity, and describing it as mu’allaq does not mean that it is regarded as da’eef (weak). There is no dispute on this point among the scholars.  
You will come across this a great deal in Saheeh al-Bukhaari. 
Al-Haafiz Ibn Hajar (may Allaah have mercy on him) said in al-Nukat (1/325): 
If the hadeeth has only one isnaad, or it includes a number of rulings and needs to be repeated, then in that case he may quote only the text of the hadeeth, or may shorten the isnaad. End quote. 
Al-Suyooti said in Tadreeb al-Raawi (1/117): 
Most of the reports of this type in al-Bukhaari appear with the full isnaad (mawsool) elsewhere in his book, but he narrated them in mu’allaq form for the sake of brevity and so as to avoid repetition. End quote. 
Thirdly: 
The ruling on a mu’allaq hadeeth is – as in the case of any other hadeeth – that it is essential to collect and examine all its isnaads. After that, the ruling must be one of the following: 
1 – If we cannot find an isnaad for it in any book, then in that case the ruling is that the hadeeth is da’eef (weak), because nothing is known about the narrators who have been omitted from the isnaad; some of them may be weak or liars. 
2 – If we find the hadeeth with an uninterrupted (mawsool) isnaad in another book of hadeeth, then in that case we have to examine the isnaad, and we judge it on the basis of the principles that the scholars have set out for examination of hadeeth. In judging the status of a mu’allaq report we may also the methodology which is stated in the books of Sunnah, as follows: 
Fourthly: 
Some of the scholars have their own methodologies of quoting mu’allaq hadeeth, which were either stated by the scholar himself or defined after him by other scholars who studied his books and examined his methods. 
From what the scholars have said about the methodology of Imam al-Bukhaari in narrating mu’allaq reports, we can divide his mu’allaq reports (of which there are one hundred and sixty) into two categories: 
1-Those which were narrated in a decisive form, such as saying “He narrated…” and so on.
The ruling on these mu’allaq reports is that they are saheeh or hasan, because it is not possible for him to state that in a decisive form unless it was saheeh in his view. Rather there are some reports which meet his conditions but he reported them in mu’allaq form. 
The scholars made an exception from this principle in the case of just one hadeeth, which is reported in mu'allaq form in the Book of Zakaah (2/525): 
Tawoos said: Mu’aadh (may Allaah be pleased with him) said to the people of Yemen: Bring an item of clothing, a shirt or other garment as zakaah instead of barley and corn; it will be easier for you, and better for the companions of the Prophet (peace and blessings of Allaah be upon him) in Madeenah. 
They said: The isnaad as far as Tawoos is saheeh, but Tawoos did not hear it from Mu’aadh.  
2-Those which are narrated as mu’allaq in a “defective” form, such as saying “It was narrated,” “it was said” etc.
Some such reports may be saheeh or hasan, and they may be reported as mu’allaq because he did not narrated them word for word, rather he narrated the meaning. 
They may also be slightly weak (da’eef), and the narrator may point out the weakness by saying “it is not saheeh.” 
(Summarized from al-Nukat by al-Haafiz Ibn Hajar (1/343-345); Tadreeb al-Raawi by al-Suyooti (1/117-121) 
With regard to Saheeh Muslim: 
There are only five mu’allaq reports in this book, which Imam Muslim narrates with one full isnaad, then after that he narrates them as mu’allaq reports with an isnaad other than the one that he gave in full, for an academic purpose that Imam Muslim wanted to achieve. They have been compiled by Shaykh Rasheed al-Deen al-‘Attaar in an essay that has been published, in which he explains their sources and saheeh isnaads. 
After the Introduction, there is no mu’allaq report in Saheeh Muslim for which he does not give a different isnaad elsewhere, except for one hadeeth. Muslim said in hadeeth no. 369: 
Al-Layth ibn Sa’d narrated from Ja’far ibn Rabee’ah from ‘Abd al-Rahmaan ibn Hormuz from ‘Umayr the freed slave of Ibn ‘Abbaas that he heard him say: ‘Abd al-Rahmaan ibn Yasaar, the freed slave of Maymoonah, the wife of the Prophet (S), and I came to Abu’l-Jahm ibn al-Haarith ibn al-Simmah al-Ansaari. Abu’l-Jahm said: The Messenger of Allaah (S) came from the direction of Bi’r Jamal and was met by a man who greeted him with salaam. The Messenger of Allaah (S) did not return the greeting until he went to a wall and wiped his face and hands, then he returned the greeting. 
See: al-Nukat by al-Haafiz Ibn Hajar (1/346-353) 
This hadeeth is found with the uninterrupted isnaad via al-Layth ibn Sa’d in Saheeh al-Bukhaari (337) and Abu Dawood (329), and elsewhere. 
And Allaah knows best.