The security vendor is warning users to update their software as soon as possible, saying this is a "high-risk" bug. All versions of ESM are vulnerable, except version 6.5.3, which includes the fixes and is not vulnerable.
A spokesman for Symantec said in an interview that the company isn't aware of any proof-of-concept code or exploits for this vulnerability.
The ESM tool is designed to discover and report vulnerabilities and security policy deviations, such as inappropriate passwords and missing patches.
The flaw lies in the fact that the tool does not authenticate someone who's making an upgrade request. That means a hacker could use the flaw to infect the system with malware.
"The vulnerability exists in the ESM agent remote upgrade interface," Symantec explained in an online advisory. "The ESM agent accepts remote upgrade requests from any entity that understands the upgrade protocol. The ESM agent does not currently verify that upgrades are from a trusted source. An attacker with knowledge of the agent protocol could deploy a piece of software that allows the attacker to control the host computer."
The ESM agent has administrative privileges.
The patch will be pushed out to users automatically, or they can manually install it, Symantec said.