certificate serialNumber is not match

[Randyshu2018]

node version:10.15.3

steps to reproduce:

1. test certificate named cert.pem:

-----BEGIN CERTIFICATE-----
MIICKjCCAdGgAwIBAgIRAMGjl2AnD3bzdpQOcPOZ944wCgYIKoZIzj0EAwIwczEL
MAkGA1UEBhMCVVMxEzARBgNVBAgTCkNhbGlmb3JuaWExFjAUBgNVBAcTDVNhbiBG
cmFuY2lzY28xGTAXBgNVBAoTEG9yZzEuZXhhbXBsZS5jb20xHDAaBgNVBAMTE2Nh
Lm9yZzEuZXhhbXBsZS5jb20wHhcNMjAwNjEyMDY0ODAwWhcNMzAwNjEwMDY0ODAw
WjBsMQswCQYDVQQGEwJVUzETMBEGA1UECBMKQ2FsaWZvcm5pYTEWMBQGA1UEBxMN
U2FuIEZyYW5jaXNjbzEPMA0GA1UECxMGY2xpZW50MR8wHQYDVQQDDBZVc2VyMUBv
cmcxLmV4YW1wbGUuY29tMFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAExkNePVH3
8oQj1J2uBWU8e1E6GuvxKy3+yutI0+d2UVrMYkfu23Z+hvKiqmXI+DX1VUTmuaF9
2du+kflKIS+Z0qNNMEswDgYDVR0PAQH/BAQDAgeAMAwGA1UdEwEB/wQCMAAwKwYD
VR0jBCQwIoAgMofBUJnNe9UyITG0/au3jfNeJ4+g377clNphXQOvfIwwCgYIKoZI
zj0EAwIDRwAwRAIgfzDtKejEx21PP/Vx2NPmaAVnAqPY30xMKAKCNVvYaSoCIAvT
1rwBNvde855LUwMGtx3mBXx13gGrCl5dXxCXZHxG
-----END CERTIFICATE-----

2. test.js

const cp = require('child_process');
const fs = require('fs');
const { Certificate } = require('@fidm/x509');

const filePath = 'cert.pem';

const cert = Certificate.fromPEM(fs.readFileSync(filePath));
console.log(`serial=${cert.serialNumber}`);

cp.spawn('openssl', [
    'x509',
    '-in',
    `${filePath}`,
    '-serial',
    "-noout"
], { stdio: "inherit" });

3. run

node test.js

4. output

serial=00c1a39760270f76f376940e70f399f78e
serial=C1A39760270F76F376940E70F399F78E