No! It does not mean mortal sins at minimum.It means ANY sin you are aware of upon reflection
Perhaps this is what you are looking for?(from the Catechism)
Why a Sacrament of Reconciliation after Baptism?
1425 "YOU were washed, you were sanctified, you were justified in the name of the Lord Jesus Christ and in the Spirit of our God."9 One must appreciate the magnitude of the gift God has given us in the sacraments of Christian initiation in order to grasp the degree to which sin is excluded for him who has "put on Christ."10 But the apostle John also says: "If we say we have no sin, we deceive ourselves, and the truth is not in us."11 and the Lord himself taught us to pray: "Forgive us our trespasses,"12 linking our forgiveness of one another's offenses to the forgiveness of our sins that God will grant us.
1426 Conversion to Christ, the new birth of Baptism, the gift of the Holy Spirit and the Body and Blood of Christ received as food have made us "holy and without blemish," just as the Church herself, the Bride of Christ, is "holy and without blemish."13 Nevertheless the new life received in Christian initiation has not abolished the frailty and weakness of human nature, nor the inclination to sin that tradition calls concupiscence, which remains in the baptized such that with the help of the grace of Christ they may prove themselves in the struggle of Christian life.14 This is the struggle of conversion directed toward holiness and eternal life to which the Lord never ceases to call us.15
9 ⇒ 1 Cor 6:11.
10 ⇒ Gal 3:27.
11 ⇒ 1 Jn 1:8[ETML:C/].
12 Cf. ⇒ Lk 11:4; ⇒ Mt 6:12.
13 ⇒ Eph 1:4; ⇒ 5:27.
14 Cf. Council of Trent (1546) DS 1515.
15 Cf. Council of Trent (1547): DS 1545; LG 40.
No! It does not mean mortal sins at minimum. It means ANY sin you are aware of upon reflection.
[From the Catechism:] 1425 "YOU were washed, you were sanctified, you were justified in the name of the Lord Jesus Christ and in the Spirit of our God."9 One must appreciate the magnitude of the gift God has given us in the sacraments of Christian initiation in order to grasp the degree to which sin is excluded for him who has "put on Christ."10 But the apostle John also says: "If we say we have no sin, we deceive ourselves, and the truth is not in us."11 and the Lord himself taught us to pray: "Forgive us our trespasses,"12 linking our forgiveness of one another's offenses to the forgiveness of our sins that God will grant us.
Well, I'm not sure I get your interpretation from the Catechism you quote. If the Catechism quotes with approval this:
1 John 1:8-10 : 8 If we claim to be without sin, we deceive ourselves and the truth is not in us. 9 If we confess our sins, he is faithful and just and will forgive us our sins and purify us from all unrighteousness. 10 If we claim we have not sinned, we make him out to be a liar and his word has no place in our lives.
Then, I would think that mortal sin is strongly implied. As I understand it, venial sin does not NEED to be confessed on threat of losing salvation. For what you're saying, the above passage COULD only be referring to venial sins. Does it really read that way to you? It doesn't to me. Plus, wouldn't that be a waste if it did only refer to venial sins without saying so? That interpretation is just too forced.