static void arc4_crypt(struct arc4_ctx *ctx, u8 *out, const u8 *in,
		       unsigned int len)
{
	u32 *const S = ctx->S;
	u32 x, y, a, b;
	u32 ty, ta, tb;

	if (len == 0)
		return;

	x = ctx->x;
	y = ctx->y;

	a = S[x];
	y = (y + a) & 0xff;
	b = S[y];

	do {
		S[y] = a;
		a = (a + b) & 0xff;
		S[x] = b;
		x = (x + 1) & 0xff;
		ta = S[x];
		ty = (y + ta) & 0xff;
		tb = S[ty];
		*out++ = *in++ ^ S[a];
		if (--len == 0)
			break;
		y = ty;
		a = ta;
		b = tb;
	} while (true);

	ctx->x = x;
	ctx->y = y;
}

This category addresses vulnerabilities caused by flawed access control mechanisms, where incorrect permission settings allow unauthorized users to access restricted resources.