diff --git a/tools/valgrind-webrtc/memcheck/suppressions.txt b/tools/valgrind-webrtc/memcheck/suppressions.txt
index 30d537a337..91ad6761c0 100644
--- a/tools/valgrind-webrtc/memcheck/suppressions.txt
+++ b/tools/valgrind-webrtc/memcheck/suppressions.txt
@@ -612,3 +612,17 @@
    fun:_ZN12_GLOBAL__N_118StatsCollectorTest22TestCertificateReportsERKN3rtc18FakeSSLCertificateERKSt6vectorISsSaISsEES4_S9_
    fun:_ZN12_GLOBAL__N_156StatsCollectorTest_ChainedCertificateReportsCreated_Test8TestBodyEv
 }
+{
+   bug_4143
+   Memcheck:Uninitialized
+   fun:Decode
+   fun:WebRtcIsac_Decode
+   fun:_ZN6webrtc9IsacFloat6DecodeEP16WebRtcISACStructPKhsPsS5_
+   fun:_ZN6webrtc24AudioEncoderDecoderIsacTINS_9IsacFloatEE6DecodeEPKhmPsPNS_12AudioDecoder10SpeechTypeE
+   fun:_ZThn8_N6webrtc24AudioEncoderDecoderIsacTINS_9IsacFloatEE6DecodeEPKhmPsPNS_12AudioDecoder10SpeechTypeE
+   fun:_ZN6webrtc9NetEqImpl10DecodeLoopEPSt4listIPNS_6PacketESaIS3_EEPNS_10OperationsEPNS_12AudioDecoderEPiPNS9_10SpeechTypeE
+   fun:_ZN6webrtc9NetEqImpl6DecodeEPSt4listIPNS_6PacketESaIS3_EEPNS_10OperationsEPiPNS_12AudioDecoder10SpeechTypeE
+   fun:_ZN6webrtc9NetEqImpl16GetAudioInternalEmPsPiS2_
+   fun:_ZN6webrtc9NetEqImpl8GetAudioEmPsPiS2_PNS_15NetEqOutputTypeE
+   fun:_ZN6webrtc35NetEqDecodingTest_DecoderError_Test8TestBodyEv
+}