src/cmd/go/testdata/script/test_fuzz_minimize_dirty_cov.txt | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/internal/fuzz/worker.go                                 | 13 ++++++++++++-

diff --git a/src/cmd/go/testdata/script/test_fuzz_minimize_dirty_cov.txt b/src/cmd/go/testdata/script/test_fuzz_minimize_dirty_cov.txt
new file mode 100644
index 0000000000000000000000000000000000000000..571bf752d000e24e0752549fe8b7792c6cfa3ccf
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_fuzz_minimize_dirty_cov.txt
@@ -0,0 +1,84 @@
+# Test that minimization doesn't use dirty coverage snapshots when it
+# is unable to actually minimize the input. We do this by checking that
+# a expected value appears in the cache. If a dirty coverage map is used
+# (i.e. the coverage map generated during the last minimization step,
+# rather than the map provided with the initial input) then this value
+# is unlikely to appear in the cache, since the map generated during
+# the last minimization step should not increase the coverage.
+
+[short] skip
+[!fuzz-instrumented] skip
+
+env GOCACHE=$WORK/gocache
+go test -fuzz=FuzzCovMin -fuzztime=25s -test.fuzzcachedir=$GOCACHE/fuzz
+go run check_file/main.go $GOCACHE/fuzz/FuzzCovMin abcd
+
+-- go.mod --
+module test
+
+-- covmin_test.go --
+package covmin
+
+import "testing"
+
+func FuzzCovMin(f *testing.F) {
+	f.Fuzz(func(t *testing.T, data []byte) {
+		if len(data) >= 4 && data[0] == 'a' && data[1] == 'b' && data[2] == 'c' && data[3] == 'd' {
+			return
+		}
+	})
+}
+
+-- check_file/main.go --
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strconv"
+)
+
+func checkFile(name, expected string) (bool, error) {
+	data, err := os.ReadFile(name)
+	if err != nil {
+		return false, err
+	}
+	for _, line := range bytes.Split(data, []byte("\n")) {
+		m := valRe.FindSubmatch(line)
+		if m == nil {
+			continue
+		}
+		fmt.Println(strconv.Unquote(string(m[1])))
+		if s, err := strconv.Unquote(string(m[1])); err != nil {
+			return false, err
+		} else if s == expected {
+			return true, nil
+		}
+	}
+	return false, nil
+}
+
+var valRe = regexp.MustCompile(`^\[\]byte\(([^)]+)\)$`)
+
+func main() {
+	dir, expected := os.Args[1], os.Args[2]
+	ents, err := os.ReadDir(dir)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+	for _, ent := range ents {
+		name := filepath.Join(dir, ent.Name())
+		if good, err := checkFile(name, expected); err != nil {
+			fmt.Fprintln(os.Stderr, err)
+			os.Exit(1)
+		} else if good {
+			os.Exit(0)
+		}
+	}
+	fmt.Fprintln(os.Stderr, "input over minimized")
+	os.Exit(1)
+}
diff --git a/src/internal/fuzz/worker.go b/src/internal/fuzz/worker.go
index e984ba73b201f0437329daa090117020daae5dc6..83d937ee6d163003c78232438ee6eb743e9ea960 100644
--- a/src/internal/fuzz/worker.go
+++ b/src/internal/fuzz/worker.go
@@ -800,6 +800,7 @@ 	vals, err := unmarshalCorpusFile(mem.valueCopy())
 	if err != nil {
 		panic(err)
 	}
+	inpHash := sha256.Sum256(mem.valueCopy())
 	if args.Timeout != 0 {
 		var cancel func()
 		ctx, cancel = context.WithTimeout(ctx, args.Timeout)
@@ -811,12 +812,22 @@ 	// to shared memory after completing minimization.
 	success, err := ws.minimizeInput(ctx, vals, mem, args)
 	if success {
 		writeToMem(vals, mem)
+		outHash := sha256.Sum256(mem.valueCopy())
 		mem.header().rawInMem = false
 		resp.WroteToMem = true
 		if err != nil {
 			resp.Err = err.Error()
 		} else {
-			resp.CoverageData = coverageSnapshot
+			// If the values didn't change during minimization then coverageSnapshot is likely
+			// a dirty snapshot which represents the very last step of minimization, not the
+			// coverage for the initial input. In that case just return the coverage we were
+			// given initially, since it more accurately represents the coverage map for the
+			// input we are returning.
+			if outHash != inpHash {
+				resp.CoverageData = coverageSnapshot
+			} else {
+				resp.CoverageData = args.KeepCoverage
+			}
 		}
 	}
 	return resp