Angry CSKA fans threw stones and invaded the pitch after Ismail Isa put the home side ahead, forcing referee Ivaylo Stoyanov to abandon the match.
The ugly scenes continued for several minutes as CSKA supporters clashed with local fans.
"The referee decided that it's impossible the game to continue," match delegate Nedelcho Mihaylov told reporters.
"We have to wait for the reports of match delegate and referees... the Bulgarian Football Union's (BFU) commissions will rule next week," said BFU press officer Pavel Kolev, adding the disciplinary commission will hold an extraordinary meeting on Monday.
"It was not normal for this match to go ahead in such conditions," said CSKA's chief executive Ventsislav Zhivkov. "We'll press for a replay."
CSKA's supporters club chairman Dimitar Angelov added: "The offenders should be punished."
CSKA's bus left the stadium under increased security.
