Unchecked fieldpath index in Composition's patches can lead to arbitrary memory allocation in crossplane

Summary

crossplane-runtime is a set of go libraries used to build Kubernetes controllers in Crossplane and its related stacks. In affected versions an already highly privileged user able to create or update Compositions can specify an arbitrarily high index in a patch's `ToFieldPath`, which could lead to excessive memory usage once such Composition is selected for a Composite resource. Compositions allow users to specify patches inserting elements into arrays at an arbitrary index. When a Composition is selected for a Composite Resource, patches are evaluated and if a specified index is greater than the current size of the target slice, Crossplane will grow that slice up to the specified index, which could lead to an excessive amount of memory usage and therefore the Pod being OOM-Killed. The index is already capped to the maximum value for a uint32 (4294967295) when parsed, but that is still an unnecessarily large value. This issue has been addressed in versions 1.11.2, 1.10.3, and 1.9.2. Users are advised to upgrade. Users unable to upgrade can restrict write privileges on Compositions to only admin users as a workaround.

Timeline

1. Mar 9, 2023, 8:22 PM UTCCVE published
2. Feb 25, 2025, 2:29 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: partial

3. Feb 25, 2025, 2:59 PM UTCRecord last updated

Affected versions

• crossplane crossplane

  fixed in 1.9.2; From 1.10.0 · fixed in 1.10.3; From 1.11.0 · fixed in 1.11.2

• github.com/crossplane/crossplaneGo

  fixed in 1.9.2

• github.com/crossplane/crossplaneGo

  From 1.10.0 · fixed in 1.10.3

• github.com/crossplane/crossplaneGo

  From 1.11.0 · fixed in 1.11.2

References 1