OSSA-2017-005: Nova Filter Scheduler bypass through rebuild action

Date:November 14, 2017


  • Nova: <=14.0.10, >=15.0.0 <=15.0.8, >=16.0.0 <=16.0.3


George Shuklin from servers.com reported a vulnerability in Nova. By rebuilding an instance, an authenticated user may be able to circumvent the Filter Scheduler bypassing imposed filters (for example, the ImagePropertiesFilter or the IsolatedHostsFilter). All setups using Nova Filter Scheduler are affected.


The former fix introduced regressions in the rebuild functionality. Rebuild may fail depending on configured scheduler filters and environment, for example, when the compute host is running at capacity or when the host is disabled. This update provides an additional set of fixes for these regressions.


  • George Shuklin from Servers.com (CVE-2017-16239)

OSSA History

  • 2017-12-05 - Errata 1
  • 2017-11-14 - Original Version