Denial of Service (DoS) vulnerability exists in the Protobuf PHP library during the parsing of untrusted input

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UBUNTU-CVE-2026-6409

A Denial of Service DoS vulnerability exists in the Protobuf PHP library during the parsing of untrusted input. Maliciously structured messages—specifically those containing negative varints or deep recursion—can be used to crash the application, impacting service availability...

PT-2026-33338

Name of the Vulnerable Software and Affected Versions Protobuf PHP versions prior to 5.34.0-RC1 Protobuf PHP versions prior to 4.33.6 Description A Denial of Service DoS issue exists during the parsing of untrusted input. Maliciously structured messages, specifically those containing negative...