SAN FRANCISCO — After acknowledging last month that hackers gained access to the personal and financial data of 38 million of its active users, Adobe Systems Inc. on Monday was targeted by a class action filed in the Northern District of California.

Adobe’s “substandard security practices and on-going security problems” left its networks and software products customers “vulnerable to attack, theft and misuse” of their personal information, Girard Gibbs partner Eric Gibbs wrote in the complaint. The lawsuit alleges breach of contract and violations of California’s data protection laws.