كتاب الحج
15  
The Book of Pilgrimage
(1)
Chapter: What one who has entered Ihram for Hajj or Umrah is permitted to wear, and what is not permissible, and perfume is forbidden for him
(1)
باب مَا يُبَاحُ لِلْمُحْرِمِ بِحَجٍّ أَوْ عُمْرَةٍ وَمَا لاَ يُبَاحُ وَبَيَانِ تَحْرِيمِ الطِّيبِ عَلَيْهِ
Sahih Muslim 1180 d

Ya'la b. Umayya (Allah be pleased with him) reported that a person came to the Messenger of Allah (ﷺ) as he was staying at Ji'rana and he had put on Ihram for 'Umra and he had dyed his beard and his head with yellow colour and there was a cloak on him. He said:

I put on Ihram for 'Umra and I am in this state as you see (with dyed beard and head and a cloak over me). He (the Holy Prophet) said: Take off the cloak and wash the yellowness and do in your 'Umra what you do in Hajj.
وَحَدَّثَنَا عُقْبَةُ بْنُ مُكْرَمٍ الْعَمِّيُّ، وَمُحَمَّدُ بْنُ رَافِعٍ، - وَاللَّفْظُ لاِبْنِ رَافِعٍ - قَالاَ حَدَّثَنَا وَهْبُ بْنُ جَرِيرِ بْنِ حَازِمٍ، حَدَّثَنَا أَبِي قَالَ، سَمِعْتُ قَيْسًا، يُحَدِّثُ عَنْ عَطَاءٍ، عَنْ صَفْوَانَ بْنِ، يَعْلَى بْنِ أُمَيَّةَ عَنْ أَبِيهِ، رضى الله عنه أَنَّ رَجُلاً، أَتَى النَّبِيَّ صلى الله عليه وسلم وَهُوَ بِالْجِعْرَانَةِ قَدْ أَهَلَّ بِالْعُمْرَةِ وَهُوَ مُصَفِّرٌ لِحْيَتَهُ وَرَأْسَهُ وَعَلَيْهِ جُبَّةٌ فَقَالَ يَا رَسُولَ اللَّهِ إِنِّي أَحْرَمْتُ بِعُمْرَةٍ وَأَنَا كَمَا تَرَى ‏.‏ فَقَالَ ‏ "‏ انْزِعْ عَنْكَ الْجُبَّةَ وَاغْسِلْ عَنْكَ الصُّفْرَةَ وَمَا كُنْتَ صَانِعًا فِي حَجِّكَ فَاصْنَعْهُ فِي عُمْرَتِكَ ‏"‏ ‏.‏
Reference : Sahih Muslim 1180d
In-book reference : Book 15, Hadith 11
USC-MSA web (English) reference : Book 7, Hadith 2657
  (deprecated numbering scheme)