diff --git a/src/core/meshcop/meshcop_tlvs.cpp b/src/core/meshcop/meshcop_tlvs.cpp
index 61b803a6e..839fe1ce5 100644
--- a/src/core/meshcop/meshcop_tlvs.cpp
+++ b/src/core/meshcop/meshcop_tlvs.cpp
@@ -189,7 +189,7 @@ bool ChannelMaskBaseTlv::IsValid(void) const
 
     VerifyOrExit(entry != nullptr);
 
-    while (reinterpret_cast<const uint8_t *>(entry) < end)
+    while (reinterpret_cast<const uint8_t *>(entry) + sizeof(ChannelMaskEntryBase) <= end)
     {
         entry = entry->GetNext();
         VerifyOrExit(reinterpret_cast<const uint8_t *>(entry) <= end);