Grading: Its chain is weak.
Technical note / Defect ('illah): Yahya bin 'Abd al-Hamid al-Himmani is weak and accused of stealing hadith; others contradicted him and narrated it as mursal, and al-Dhahabi declared it defective in "al-Talkhis" because of al-Himmani. The other narrator, Abu Ishaq ('Amr bin 'Abd Allah al-Sabi'i), is a mudallis, and no hearing of his from Abu Salamah (Ibn 'Abd al-Rahman bin 'Awf) is known. There is also disagreement over this hadith in the narrations from Abu Ishaq, as will come.

Reference / Source: Abu Dawud recorded it in "al-Marasil" (371), and through him al-Bayhaqi (6/224), from Husayn bin 'Ali bin al-Aswad, from Yahya bin Adam, from 'Ammar bin Ruzayq, from Abu Ishaq, from Abu Salamah, as mursal.

Grading: After it al-Bayhaqi said: "The hadith of Abu Ishaq from Abu Salamah is munqati' and not well known."
Technical note / Defect ('illah): We say: Husayn bin 'Ali bin al-Aswad is also weak.

Reference / Source: Al-Tabari recorded it in his "Tafsir" (6/44) through the route of Zakariyya bin Abi Za'idah, and Ibn Abi Hatim (as in "al-'Ilal" 1639) through the route of Yunus bin 'Amr al-Sabi'i; both of them from Abu Ishaq, from Abu Salamah, as mursal, but without the explanation of kalalah.
Technical note / Defect ('illah): Abu Hatim said about the mursal narration: "It is the more likely (al-ashbah)."

Details of the narration: A group narrated it from Abu Ishaq, from al-Bara' bin 'Azib, without the explanation of kalalah as marfu': Abu Bakr bin 'Ayyash [Ahmad (30/18589), Abu Dawud (2889), al-Tirmidhi (3042)], Hajjaj bin Artah [Ahmad (18607, 18677) and others], and Ajlah bin 'Abd Allah bin Hujayyah [as mentioned by Ibn Abi Hatim in "al-'Ilal" (1639)]; they made it part of the Musnad of al-Bara' bin 'Azib. Al-Bayhaqi said: "This is the well-known version." Ibn Kathir said in his "Tafsir": "This chain is good (jayyid)."
Corroborating chains and supporting reports: We say: the hadith of al-Bara' is supported by the hadith of 'Umar recorded by Muslim (567).