Researchers have disclosed a critical vulnerability in the latest version of Mac OS X that they say Apple has sat on for almost seven months without fixing.

The buffer overflow flaw could be exploited by attackers to remotely execute malicious code, and virtually all Apple devices - including Mac computers and servers, iPhones, and even Apple TV - are susceptible, one of the researchers, Maksymilian Arciemowicz, told The Register. SecurityReason.com, the Poland-based security firm he works for, alerted Apple to the vulnerability in the middle of June and again last month, but the computer maker has yet to patch the bug.

By contrast, developers for OpenBSD, NetBSD, FreeBSD, and a variety of Mozilla applications have fixed identical vulnerabilities, in some cases within hours of notification. The bug affects all applications and operating systems that implement gdtoa floating point numbers.

"It was not that difficult to patch it," Arciemowicz wrote in an email. "It seems to us that Apple comes from the assumption that when there is no PoC or exploit given that the problem doesn't exist."

The OS X bug resides in the libc/strtod(3) and libc/gdtoa function. Arciemowicz said the vulnerability could be remotely exploited using booby-trapped PHP code on a website, among other methods.

SecurityReason has posted proof-of-concept code here that shows how the flaw can be exploited to make a machine crash. With additional work - specifically, by manipulating esi and edi registers - it is possible to remotely execute code, Arciemowicz said.

Of the 16 applications or systems known to be affected by the bug, only four remain vulnerable. In addition to OS X, they include Mozilla Sunbird, K-Meleon, and the J programming language. ®