There is no explicit mention of Buddha or Buddhism. However, Nilakantha the 16th century commentator of Mahabharata, whose commentary is used by Mahabharata translators, claims to see the mention of Buddhism in Santi Parva. I think Nilakantha is right that the bolded parts in Vyasa's speech are clearly referring to Buddhism.
"Suka said, 'What is that Knowledge? Is it that learning by which,
when error is dispelled, the truth becomes discovered? Or, is it that
course of duties consisting of acts to be done or achieved, by the aid
of which the object sought may be understood or attained? Or, is it
that course of duties, called abstention from acts, by which an
extension of the Soul is to be sought? Do tell me what it is, so that
by its aid, the two, viz., birth and death, may be avoided.' 1
"Vyasa said, 'That fool who believing that all this exists in
consequence of its own nature without, in fact, an existent refuge or
foundation, fills by such instruction the aspirations of disciples,
dispelling by his dialectical ingenuity the reasons the latter might
urge to the contrary, succeeds not in attaining to any truth. 2 They
again who firmly believe that all Cause is due to the nature of
things, fail to acquire any truth by even listening to (wiser) men or
the Rishis (who are capable of instructing them). 3 Those men of
little intelligence who stop (in their speculations), having adopted
either of these doctrines, indeed, those men who regard nature as the
cause, never succeed in obtaining any benefit for themselves. 4 This
belief in Nature (as the producing and the sustaining Cause), arising
as it does from a mind acting under the influence of error, brings
about the destruction of the person who cherishes it. Listen now to
the truth with respect to these two doctrines that maintain (1) that
things exist by their own nature and (2) that they flow (in
consequence of their own nature) from others that are different from
and that precede them. 5 Wise men apply themselves to agriculture and
tillage, and the acquisition of crops (by those means) and of vehicles
(for locomotion) and seats and carpets and houses. They attend also to
the laying of pleasure-gardens, the construction of commodious
mansions, and the preparation of
Footnotes
172:6 Brahmanam is arsha for Brahmam.
173:1 I follow Nilakantha's gloss in rendering the words Vidya,
Pravritti and Nivritti, as used in this verse. By the first, the
commentator thinks, is meant that course of instruction in consequence
of which error may be dispelled and truth acquired. The usual
illustration of the cord and the snake is given. The former maybe
mistaken for the latter, but when the mistake ceases, correct
apprehension follows. Pravritti has been sufficiently indicated in the
text in which the words of the gloss has been incorporated. By
Nivritti is meant the doctrine of the Sunyavadins and Lokayatikas
(evidently the Buddhists) who seek annihilation or extinction as
the only true Emancipation. Both the Vernacular translators are wrong.
The Burdwan translator, as usual, citing the very words of the gloss,
misunderstands them completely.
173:2 The construction of the first line is 'yastu achetanah bhavam
vina swabhavena (sarvam bhati iti) pasyan, etc., etc., pushyate (sa na
kinchana labhate).' Bhavan is explained as 'adhishthanasattam.' The
commentator is of opinion that the speaker refers in this verse to the
Sunyavadins.
173:3 The Bombay text reads Putwatrinamishikamva.
173:4 Enam is singular. The commentator thinks it should be taken
distributively. In verse 3, the doctrine of the Nihilists
(Sunyavadins) has been referred to. In verse 4, that of the
Lokayatikas. In both, Nature is spoken of as the cause, with this
difference that the former regard the universe to be only an erroneous
impression of an existent entity, while the latter regard it as a real
entity flowing from and manifesting itself under its own nature. Both
doctrines, the speaker says, are false.
Mahabharata Santi Parva, Section CCXXXVII, English translation by Kishori Mohan Ganguli
