I was wondering whether criticizing the Vedas is a condemnable offence. In other religions, usually condemning the scripture can have a severe consequence. What about Hinduism?
There is a punishment. TL;DR -- Criticizing the Vedas is an act of a Pisaca, a mortal sin, and causes loss of caste.
atha patanīyāni || 7 ||
7. Now [follows the enumeration of] the actions which cause loss of caste [Pataniya].
steyam ābhiśastyaṃ puruṣa vadho brahma ujjhaṃ garbha śātanam mātuḥ pitur iti yoni saṃbandhe saha-apatye strī gamanaṃ surā pānam asaṃyoga saṃyogaḥ || 8 ||
8. [These are] (a) stealing [gold], (b) crimes whereby one becomes an Abhiśasta, (c) homicide, (d) neglect of the Vedas, (e) causing abortion, (f) incestuous connection with maternal or paternal uncles or aunts, (g) and with the offspring of such persons (cousins), (h) alcoholism, and (i) socializing with persons the interaction with whom is forbidden.
Apastamba Sutra 1.7.21
By Apastamba Sutra, neglect of the Vedas (which occurs with criticism) causes loss of caste.
4.163. Let him avoid atheism, cavilling at the Vedas, contempt of the gods, hatred, want of modesty, pride, anger, and harshness
11.56. Forgetting the Veda, reviling the Vedas, giving false evidence, slaying a friend, eating forbidden food, or (swallowing substances) unfit for food, are six (offences) equal to drinking Sura.
Manu Smriti equals the punishment of criticizing the Vedas to the punishment of drinking Sura. Now, let's see what happens when you drink Sura.
9.237. For violating a Guru’s bed, (the mark of) a female part shall be (impressed on the forehead with a hot iron); for drinking (the spirituous liquor called) Sura, the sign of a tavern; for stealing (the gold of a Brahmana), a dog’s foot; for murdering a Brahmana, a headless corpse.
11.54. Killing a Brahmana, drinking (the spirituous liquor called) Sura, stealing (the gold of a Brahmana), adultery with a Guru’s wife, and associating with such (offenders), they declare (to be) mortal sins (mahapataka).
11.95. Sura, (all other) intoxicating drinks and decoctions and flesh are the food of the Yakshas, Rakshasas, and Pisakas; a Brahmana who eats (the remnants of) the offerings consecrated to the gods, must not partake of such (substances).
11.97. When the Brahman (the Veda) which dwells in his body is (even) once (only) deluged with spirituous liquor, his Brahmanhood forsakes him and he becomes a Sudra.
The last verse agrees with Apastamba in that criticizing the Vedas causes loss of caste. However, Manu Smriti expands by saying that it is a mortal sin and that criticizing the Vedas is an act of a Pisaca. This agrees with Sanantan Darshan's answer as well.
According to Skanda Purana V.ii.68.24-33 , one who speaks wrong about vedas and gods becomes pishacha.
Those who commit breach of trust, those who have sex with other men’s wives and those who speak ill of the Vedas, attain the state of Piśāca. Men who always decry the Purāṇas and Dharmaśāstras and who calumniate others become Piśācas.
Other scriptures prescribes hell for these people.
A rejector of proofs, a slanderer of the interpretation of the Vedic scriptures, a transgressor urged by lust and covetousness, that fool goeth to hell.”
Vana Parva Section III
Brahma Purana 106.135 “There is a hell named Atratistha. It contains putrescent urine and faeces. Those who censure Smrtis and the Vedas fall into it with faces downwards.”
Brahma Vaivarta Purana, Krishna Janma Khanda 40.116-141 “…A sinner who slanders Brahma, the creator of the world, the goddess Durga who is the best of female deities, Laksmi, Saraswati, Sita, Tulsi, Ganga, the Vedas, the mother of the Vedas, a vow, devotion, mystic formula pertaining to worship of the spiritual guide who gives formula will dwell in the hell called the ‘Blind well’ for half the period of the longevity allotted to Brahma, where bitten by snakes he will scream dreadfully.