Yes - gem diols are favored by electron withdrawing groups adjacent to the carbonyl.
Gem-diols are also called aldehyde or ketone hydrates - for most aldehydes, the gem diol (hydrate) form is dominant in water solution, but with removal of water the equilibrium shifts back to the aldehyde. Ketones show less hydrtae formation without special characteristics.
The classic "stable, isolatable" gem diols are chloral hydrate (CCl3CH(OH)2) and ninhydrin.
cyano acetaldehyde will be more stable bu probably not enough to be isolated.
a hydroxy group is a pi donor but sigma withdrawing - the effect is less predictable for 2-hydroxyacetaldehyde (glycolaldehyde). This is an interesting molecule - exists independently mostly as a dimer, but in water is mostly the hydrate.