An Oak Cliff school learned the hard way about Zoom security last week.

Images of child pornography appeared on the screen during an online meeting between administrators, parents and students of Townview High School in Oak Cliff.

About 60 people were in the meeting at the time WFAA reports.

Dallas ISD apologized:

We apologize for the graphic images some of our students and families may have seen during a parent-senior Zoom meeting, which was hacked by an unknown source yesterday. It’s unfortunate the digital platform that many of us rely on to connect students with teachers each day, has been compromised through various ‘Zoom-bombings.’ Though we are disappointed the incident occurred, campus administrators successfully restarted the meeting without further incident and are working with Dallas ISD Police to investigate. A formal complaint was reported to Zoom, as we hope this incident prompts a stronger review of their security measures.

But DISD schools have a history of making links to Zoom meetings public on the district’s website and not requiring passwords to join Zoom meetings.

Computer science professor Murat Kantarcioglu of the University of Texas at Dallas says Zoom meeting links and passwords should never be made available to the public at large.