What is the origin of the curren Vietnamese flag?
Here’s the Flags of the World site talking about it.
Paraphrased from the Communist Party of Vietnam’s web page:
The golden-starred red flag was first used in November 23, 1940, during an uprising against the French troops in Nam Ku. President Ho Chi Minh signed a decree adopting this flag as the National Flag on September 5, 1945.
(My browser didn’t decode the Vietnamese characters properly, hence the paraphrasing.)