CVE-2026-6409
Published:April 16, 2026
Updated:April 23, 2026
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.
Affected Packages
https://github.com/protocolbuffers/protobuf.git (GITHUB):
Affected version(s) >=v34.0-rc1.1 <v34.0-rc1.1Fix Suggestion:
Update to version v34.0-rc1.1https://github.com/protocolbuffers/protobuf.git (GITHUB):
Affected version(s) >=v2.4.1 <v33.6Fix Suggestion:
Update to version v33.6google/protobuf (PHP):
Affected version(s) >=v2.4.1 <v4.33.6Fix Suggestion:
Update to version v4.33.6Related Resources (7)
Do you need more information?
Contact UsCVSS v4
Base Score:
7.1
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
PASSIVE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
6.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
EPSS
Base Score:
0.07
