diff --git a/libprocessgroup/processgroup.cpp b/libprocessgroup/processgroup.cpp
index d5f3ad3c2e7b77ab0ef80aa26d201a76cf9da8cd..49f5903dcb043f4c7ff09af54f84febba75b3c5b 100644
--- a/libprocessgroup/processgroup.cpp
+++ b/libprocessgroup/processgroup.cpp
@@ -99,7 +99,7 @@ static int refillBuffer(struct ctx *ctx)
     }
 
     ctx->buf_len += ret;
-    ctx->buf[ctx->buf_len-1] = 0;
+    ctx->buf[ctx->buf_len] = 0;
     SLOGV("Read %d to buffer: %s", ret, ctx->buf);
 
     assert(ctx->buf_len <= sizeof(ctx->buf));