Firefox 22.214.171.124 patched ten vulnerabilities, including three critical flaws, but also shipped with five regression bugs -- problems unintentionally introduced when code was changed to plug other holes.
"Most users won’t see any difference or experience any problems," said Mike Beltzner of Mozilla in a posting to the company's development center blog. "We’re working fast to understand and fix these problems, and will shortly be issuing a 126.96.36.199 update to address them."
According to notes from a weekly Mozilla meeting on Firefox, the regression reports began accumulating over the weekend. Firefox 188.8.131.52 was posted for download late Wednesday, Oct. 17. Three of the five problems were limited to Windows, but two page rendering issues affected all versions of the browser, including those for Mac OS X and Linux.
The Windows-specific bugs included one that disables Firefox extensions after updating. The problem doesn't affect every copy of 184.108.40.206 on Windows -- one user said it had hit just one of his four PCs -- and can be remedied by deleting a trio of files from the hard drive. Programmers are still working on a fix.
Another under the microscope, however, has no workaround. Firefox 220.127.116.11 crashes on startup on some Windows XP and Vista systems, a listing in Mozilla's bug reporting database said, and although developers quickly came up with a test to reproduce the crash, they seemed unsure whether they were on the right track. "This seems to have been fixed on trunk (regarding the test case) between 2007-08-21 and 2007-08-22," said Martijn Wargers.
"Hmm. I wonder whether we're hitting EM restart weirdness here or something," replied another developer, Boris Zbarsky.
Beltzner said Mozilla hoped to put a new Firefox, version 18.104.22.168, into the pipeline next week.
This isn't the first time that the open-source developer has scrambled to set things right. In March, it release Firefox 22.214.171.124 and 126.96.36.199 to fix several regressions that slipped into the prior versions, which hit the street the month before.