Adobe said its Connect web conferencing service and other company sites were not breached.
News of the breach surfaced on Tuesday when a hacker claimed in a posting on the Internet to have stolen log-in credentials of 150,000 Adobe customers and partners.
The hacker, who claimed to be from Egypt, released 644 records from the site, including emails, saying the release was done to point out that Adobe is slow in fixing security problems.
The hacker also promised to release data stolen from Yahoo Inc. A Yahoo spokeswoman did not respond to a request for comment.
The Adobe breach was discovered a week after Russian security firm Group-IB said it had uncovered a flaw in Adobe's Reader software that criminals are currently exploiting to attack PCs by infecting them with malicious PDF documents.
Adobe spokeswoman Wiebke Lips said the company is still reviewing that report, though it has not yet received samples of malicious code discovered by Group-IB.