The incident allegedly occurred in the red camping area of the music festival between 10pm and 11pm on Saturday 20 July, according to Suffolk Police.
Police said specialist trained officers are working with the victim while initial enquiries into the attack take place.
Alongside the statement, police reiterated safety advice for festival-goers, urging those attending festivals to stick with their friends, stay in groups and learn the layout of their chosen festival to avoid getting lost.
“Festivals give you the opportunity to meet new friends but going off alone with people who you’ve just met may lead you into situations you don’t want to be in,” they said. “Remember no means no.”
Snow Patrol were supposed to headline the four-day festival’s Saturday night but were forced to pull out after two band members were unable to play due to medical reasons.
Nearly half of female festival-goers (43 per cent) under the age of 40 said they had faced unwanted sexual behaviour at a festival.
However, only 2 per cent of incidents of sexual harassment or assault were reported to police, according to YouGov’s survey.
Jen Calleja, co-director of the Good Night Out campaign against sexual harassment and assault, said the research was "shocking but not surprising".
"We know that the vast amount of harassment and sexual assault is not reported and we know this comes down to stigma, fear of not being believed and a minimisation of what harassment is,” she said.
Latitude Festival has been contacted for comment.
Police are asking anyone with information about the incident on Saturday to contact the East Safeguarding Unit in Lowestoft quoting reference 42731/19.
Alternatively, anyone with information can contact Crimestoppers anonymously on 0800 555 111.