Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
tabarani:106Muṭṭalib b. Shuʿayb al-Azdī > ʿAbdullāh b. Ṣāliḥ > al-Layth > ʿAbdullāh b. ʿUmar > Ibn Shihāb > al-Miswar b. Makhramah > Kānat

[Machine] "The caliphate of Uthman lasted for twelve years."  

الطبراني:١٠٦حَدَّثَنَا مُطَّلِبُ بْنُ شُعَيْبٍ الْأَزْدِيُّ ثنا عَبْدُ اللهِ بْنُ صَالِحٍ حَدَّثَنِي اللَّيْثُ حَدَّثَنِي عَبْدُ اللهِ بْنُ عُمَرَ عَنِ ابْنِ شِهَابٍ عَنِ الْمِسْوَرِ بْنِ مَخْرَمَةَ قَالَ

«كَانَتْ خِلَافَةُ عُثْمَانَ ؓ ثِنْتَيْ عَشْرَةَ سَنَةً»