OSSA-2026-016: Neutron tagging policy bypass allows project readers to mutate tags

Date:

May 28, 2026

CVE:

CVE-2026-pending

Affects

  • Neutron: >=26.0.0 <26.0.4, >=27.0.0 <27.0.3, >=28.0.0 <28.0.1

Description

Tim Shephard from roiai.ca reported a policy enforcement bypass in Neutron’s tagging controller. The controller enforces plural policy action names on single-tag write operations while the defined policy rules use singular names. The mismatched names evaluate as allowed under default policy, permitting a project reader to create and update tags on same-project resources. Deployments running Neutron 26.0.0 or later are affected.

Patches

Credits

  • Tim Shephard from roiai.ca (CVE-2026-pending)

References

Notes

  • CVE assignment is pending (MITRE CAN-2026-2030611).