diff --git a/sanitizers/suppressions/asan.supp b/sanitizers/suppressions/asan.supp
index 73a44f3b71..75436e27eb 100644
--- a/sanitizers/suppressions/asan.supp
+++ b/sanitizers/suppressions/asan.supp
@@ -7,6 +7,7 @@
 # - stack-use-after-return errors
 # - stack-use-after-scope errors
 # - stack-buffer-overflow errors in seemingly unrelated code (e.g., std::chrono::steady_clock::now())
+# - stack-buffer-underflow errors in seemingly unrelated code (e.g., xxhasher::retrieveHash(), clock_gettime)
 #
 # These are suppressed via:
 # 1. Runtime option: detect_stack_use_after_return=0 (in ASAN_OPTIONS in CI workflow)
diff --git a/sanitizers/suppressions/sanitizer-ignorelist.txt b/sanitizers/suppressions/sanitizer-ignorelist.txt
index 5dbead48a2..278b843168 100644
--- a/sanitizers/suppressions/sanitizer-ignorelist.txt
+++ b/sanitizers/suppressions/sanitizer-ignorelist.txt
@@ -27,3 +27,8 @@ src:core/JobQueue.cpp
 src:libxrpl/beast/utility/beast_Journal.cpp
 src:test/beast/beast_PropertyStream_test.cpp
 src:src/test/app/Invariants_test.cpp
+
+# Boost coroutines cause false positive stack-buffer-underflow in xxhasher
+# This is a known ASAN limitation with stackful coroutines
+# See: https://github.com/google/sanitizers/issues/189
+src:beast/hash/xxhasher.h
diff --git a/sanitizers/suppressions/ubsan.supp b/sanitizers/suppressions/ubsan.supp
index dc821f8d30..a5faf565af 100644
--- a/sanitizers/suppressions/ubsan.supp
+++ b/sanitizers/suppressions/ubsan.supp
@@ -129,6 +129,7 @@ unsigned-integer-overflow:string_view
 # runtime error: unsigned integer overflow: 0 - 1 cannot be represented in type 'std::size_t' (aka 'unsigned long')
 unsigned-integer-overflow:src/libxrpl/basics/base64.cpp
 unsigned-integer-overflow:src/libxrpl/basics/Number.cpp
+unsigned-integer-overflow:src/libxrpl/basics/Number.h
 unsigned-integer-overflow:src/libxrpl/crypto/RFC1751.cpp
 unsigned-integer-overflow:rc/libxrpl/json/json_value.cpp
 unsigned-integer-overflow:src/libxrpl/ledger/ApplyView.cpp
diff --git a/src/libxrpl/json/json_value.cpp b/src/libxrpl/json/json_value.cpp
index b738774d79..5da1da7c42 100644
--- a/src/libxrpl/json/json_value.cpp
+++ b/src/libxrpl/json/json_value.cpp
@@ -198,17 +198,17 @@ Value::Value(ValueType type) : type_(type), allocated_(0)
     }
 }
 
-Value::Value(Int value) : type_(intValue)
+Value::Value(Int value) : type_(intValue), allocated_(0)
 {
     value_.int_ = value;
 }
 
-Value::Value(UInt value) : type_(uintValue)
+Value::Value(UInt value) : type_(uintValue), allocated_(0)
 {
     value_.uint_ = value;
 }
 
-Value::Value(double value) : type_(realValue)
+Value::Value(double value) : type_(realValue), allocated_(0)
 {
     value_.real_ = value;
 }
@@ -236,7 +236,7 @@ Value::Value(StaticString const& value) : type_(stringValue), allocated_(false)
     value_.string_ = const_cast<char*>(value.c_str());
 }
 
-Value::Value(bool value) : type_(booleanValue)
+Value::Value(bool value) : type_(booleanValue), allocated_(0)
 {
     value_.bool_ = value;
 }