Python Facebook Thrift servers would not error upon receiving messages with containers of fields of unknown type. As a result, malicious clients could send short messages which would take a long time for the server to parse, potentially leading to denial of service. This issue affects Facebook Thrift prior to v2019.02.18.00.

References

• https://nvd.nist.gov/vuln/detail/CVE-2019-3558
• facebook/fbthrift@c5d6e07
• https://lists.apache.org/thread.html/rd0e44e8ef71eeaaa3cf3d1b8b41eb25894372e2995ec908ce7624d26@%3Ccommits.pulsar.apache.org%3E
• https://www.facebook.com/security/advisories/cve-2019-3558
• http://www.securityfocus.com/bid/108274