diff --git a/CHANGELOG.md b/CHANGELOG.md
index 75a6be09..425d121e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -27,6 +27,8 @@ will consitute of a breaking change warranting a new major release:
 
 ## Fixed
 
+- Fixed wrong dimension of a matrix within the `MEKF`, which would lead to a seg fault, if the
+  star tracker was available.
 - Fixed case in which control values within the `AcsController` could become NaN.
 
 # [v7.7.0] 2024-02-29
diff --git a/mission/controller/acs/MultiplicativeKalmanFilter.cpp b/mission/controller/acs/MultiplicativeKalmanFilter.cpp
index c6431aa2..5dce2a84 100644
--- a/mission/controller/acs/MultiplicativeKalmanFilter.cpp
+++ b/mission/controller/acs/MultiplicativeKalmanFilter.cpp
@@ -342,7 +342,7 @@ ReturnValue_t MultiplicativeKalmanFilter::kfGain(
     double *measSensMatrix, double *measCovMatrix, double *kalmanGain,
     acsctrl::AttitudeEstimationData *attitudeEstimationData) {
   // Kalman Gain: K = P * H' / (H * P * H' + R)
-  double kalmanGainDen[6][matrixDimensionFactor] = {{0}},
+  double kalmanGainDen[matrixDimensionFactor][matrixDimensionFactor] = {{0}},
          invKalmanGainDen[matrixDimensionFactor][matrixDimensionFactor] = {{0}},
          residualCov[6][matrixDimensionFactor] = {{0}},
          measSensMatrixTransposed[6][matrixDimensionFactor] = {{0}};