system
Provide references for <CVE-2021-3902>.
user
Where can I find more information about <CVE-2021-3902>?
assistant
References are available at: https://huntr.com/bounties/a6071c07-806f-429a-8656-a4742e4191b1, https://github.com/dompdf/dompdf/commit/f56bc8e40be6c0ae0825e6c7396f4db80620b799.