Zanib Khan,27, has admitted having been "stupid", The Sun reported.
Khan also shared intimate calls with men on mobile phones smuggled into Brixton Jail, South London. She may now face jail after admitting misconduct in a public office.
She had "inappropriate relationships" with three prisoners aged 28 or 29, Southwark Crown Court heard. They are thought to include drug dealers. Police believe she was also close to four other lags over a three-year period.
Khan, of Ilford, East London, said she hoped of getting community service when she would be sentenced this week, but she could be jailed.
Scotland Yard's London Prison Anti-Corruption Team, however, has found no evidence to suggest any of her relationships had been sexual.