CVE-2026-6409

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

State: Published
Severity: 7.1 High
Published: Apr 16, 2026
Updated: Apr 16, 2026
Reserved: Apr 15, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
4.0	7.1 High	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N	Google

Weaknesses

CWE-20 Improper input validation

Affected Products

Product	Versions
Protobuf-php (Pecl)Protocol Buffers	before 5.34.0-RC1Affected before 4.33.6Affected

References

https://github.com/protocolbuffers/protobuf/security/advisories/GHSA-p2gh-cfq4-4wjc

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