diff --git a/browser/config/mozconfigs/linux64/asan-fuzzing-ccov b/browser/config/mozconfigs/linux64/asan-fuzzing-ccov
index b1dfe5105280..6f4671dbcabc 100644
--- a/browser/config/mozconfigs/linux64/asan-fuzzing-ccov
+++ b/browser/config/mozconfigs/linux64/asan-fuzzing-ccov
@@ -21,9 +21,9 @@ ac_add_options --disable-profiling
 ac_add_options --disable-warnings-as-errors
 ac_add_options --enable-coverage
 
-export CFLAGS="--coverage"
-export CXXFLAGS="--coverage"
-export LDFLAGS="--coverage -Wl,--compress-debug-sections=zlib"
+export CFLAGS="$CFLAGS --coverage"
+export CXXFLAGS="$CXXFLAGS --coverage"
+export LDFLAGS="$LDFLAGS --coverage -Wl,--compress-debug-sections=zlib"
 
 # gold is required for libFuzzer to work properly
 ac_add_options --enable-linker=gold