NASA actually has a post on what the statuses of the flags are; they are probably bleached or disintegrated.[1] Interestingly, I would guess that the flag most likely to have survived would be the one from Apollo 11, because it was too close to the lander, and got knocked over by the ascent module; it may have been covered with dust and protected, but this is only a remote possibility.
note: the post says that the LROC shows shadows from the flags, but it seems highly unlikely they are pristine or even intact.
There's even the reverse - People who claim they can pinpoint the U.S moon flag with a telescope, trying their hardest to convince others the landings were real.
