diff --git a/src/basic/journal-importer.h b/src/basic/journal-importer.h
index 3c98d905da..53354b7c78 100644
--- a/src/basic/journal-importer.h
+++ b/src/basic/journal-importer.h
@@ -12,8 +12,13 @@
 
 /* Make sure not to make this smaller than the maximum coredump size.
  * See JOURNAL_SIZE_MAX in coredump.c */
+#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 #define ENTRY_SIZE_MAX (1024*1024*770u)
 #define DATA_SIZE_MAX (1024*1024*768u)
+#else
+#define ENTRY_SIZE_MAX (1024*1024*13u)
+#define DATA_SIZE_MAX (1024*1024*11u)
+#endif
 #define LINE_CHUNK 8*1024u
 
 struct iovec_wrapper {
diff --git a/src/coredump/coredump.c b/src/coredump/coredump.c
index 440d13d157..0ca8b3f00e 100644
--- a/src/coredump/coredump.c
+++ b/src/coredump/coredump.c
@@ -55,7 +55,12 @@
 #define EXTERNAL_SIZE_MAX PROCESS_SIZE_MAX
 
 /* The maximum size up to which we store the coredump in the journal */
+#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 #define JOURNAL_SIZE_MAX ((size_t) (767LU*1024LU*1024LU))
+#else
+/* oss-fuzz limits memory usage. */
+#define JOURNAL_SIZE_MAX ((size_t) (10LU*1024LU*1024LU))
+#endif
 
 /* Make sure to not make this larger than the maximum journal entry
  * size. See DATA_SIZE_MAX in journal-importer.h. */