From 263a7f8e61c04b07e5da6d2b7883c48a738ade1c Mon Sep 17 00:00:00 2001
From: Alex Lindsay <alexander.lindsay@inl.gov>
Date: Thu, 4 Apr 2024 18:54:48 -0700
Subject: [PATCH] Limit _stage variable to prevent OOB access

Refs #27231
---
 framework/src/timeintegrators/ExplicitSSPRungeKutta.C | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/framework/src/timeintegrators/ExplicitSSPRungeKutta.C b/framework/src/timeintegrators/ExplicitSSPRungeKutta.C
index 91563677f8bc..45ecd23ef490 100644
--- a/framework/src/timeintegrators/ExplicitSSPRungeKutta.C
+++ b/framework/src/timeintegrators/ExplicitSSPRungeKutta.C
@@ -136,6 +136,12 @@ ExplicitSSPRungeKutta::solve()
     if (!converged)
       return;
   }
+
+  if (_stage == _n_stages)
+    // We made it to the end of the solve. We may call functions like computeTimeDerivatives later
+    // for postprocessing purposes in which case we need to ensure we're accessing our data
+    // correctly (e.g. not out-of-bounds)
+    --_stage;
 }
 
 bool