Input validation error in protobuf - CVE-2026-6409
Published: March 24, 2026
Vulnerability identifier: #VU124260
CSH Severity: Medium
CVSS v4 BT: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]
CVE-ID: CVE-2026-6409
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to insufficient validation of user-supplied input in the Protobuf PHP library. A remote attacker can pass specially crafted input to the application and perform a denial of service (DoS) attack.
Affected software
protobuf
How to mitigate CVE-2026-6409
Install updates from vendor's website.
protobuf - addressed in versions 4.33.6, 5.34.0 rc1