diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1879d72d..21606d65 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,9 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Added
 * `FromPyObject` implementations for `HashSet` and `BTreeSet`. [#842](https://github.com/PyO3/pyo3/pull/842)
 
+### Fixed
+- Garbage Collector causing random panics when traversing objects that were mutably borrowed. [#855](https://github.com/PyO3/pyo3/pull/855)
+
 ## [0.9.1]
 
 ### Fixed