Google’s Project Zero vulnerability research group has drawn some flak recently for its practice of publicly disclosing security flaws in software from other vendors after a 90-day notice period, regardless of whether patches are available or not.

Friday, the company may have gotten a small taste of its own medicine when Polish firm Security Explorations Friday released details on several unpatched vulnerabilities in Google’s cloud software after the Internet giant allegedly failed to respond in a timely manner to the issue.

The vulnerabilities in Google’s App Engine (GAE) software include three complete Java sandbox escapes that could be used to gather a lot of information on the Java Runtime Environment sandbox itself. “They also seem to be a potentially good starting point to proceed with attacks against the OS sandbox and RPC services visible to the sandboxed Java environment,” Adam Gowdiak, CEO of Security Explorations said in emailed comments to Dark Reading.

In addition to the flaws, Security Explorations also released proof of concept code showing how the vulnerabilities can be exploit to bypass the Java security sandbox in GAE.

Google’s App Engine is a hosted service for enterprises seeking to run and maintain applications in the cloud.

This is the second time in less than six months that Security Explorations has uncovered holes in the technology. In December, the company disclosed a total of 31 security issues in the software, including 22 that allowed an escape from the Java security sandbox.

Google patched those flaws by mid-March, Gowdiak said. Following that, between March and April, Security Explorations reported an additional 10 issues to Google, of which seven were publicly disclosed today, he added.

“The security issues published today need to be combined together in order to conduct a successful attack. In that context, it's difficult to point to a single one that's the most serious,” Gowdiak said. The Java security sandbox escape exploit was the most that Security Explorations could achieve given the constraints under which it conducted the vulnerability research on GAE, he said.

For Google, the disclosures by Security Explorations have become a sort of test of its own tolerance for bug disclosures for which no patches are immediately available. The disclosure also focuses attention once again on the issue of responsible bug disclosure practices, especially at a time when enterprises need all the protection they can from software vendors.

Many security researchers and vendors acknowledge that the safest way to publicly disclose bugs in software products is after the vendor has had a chance to fix it. But there is considerable debate on just how much notice is reasonable enough for a vendor to address the issue.

Google itself has maintained that a 90-day window is more than enough time for a fix. But some within the industry have been irritated by the company’s refusal—till recently at least—to budge from that deadline.

In January, Microsoft’s senior director of Trustworthy Computing Chris Betz, raked Google through the coals for publicly releasing information on a flaw in a Microsoft product, just two days before a scheduled Patch Tuesday fix for it.

Although sticking to a deadline is good policy, Google’s decision to go public with the flaw despite knowing about the fix, “feels less like principles and more like a “gotcha,” with customers the ones who may suffer as a result,” Betz had noted. Contrary to perception, publicly releasing information on a flaw without context or further protections, “unduly pressures an already complicated technical environment,” he had said.

Following the criticism, Google loosened its disclosure policy a bit and now gives vendors a grace period beyond 90 days in certain cases.

Google did not respond to a request for comment.

It’s unclear how the company’s views the latest disclosures by Security Explorations. Back in December, the security firm claimed Google initially suspended its GAE account following the disclosures. Later, the company announced that it had received a reward of  $50,000 from Google for finding the bugs.

This time around, Gowdiak says he gave Google three weeks to confirm or deny the reported flaws. “They were fully documented and accompanied by Proof of Concept codes,” he said.

Gowdiak said Security Explorations does not follow a strict rule for vulnerability disclosures. “If a vulnerability is confirmed by a vendor and we are provided with status updates regarding the patching process, we usually wait …until the patches are released. “