VulnerabilityAwaiting Analysis

CVE-2026-6409

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

HIGH 7.1EPSS 0.36%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.36%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 4.0: 7.1 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.36% probability · 29th percentile
CISA KEV: Not listed
Weakness: CWE-20
Source: cve-coordination@google.com

References

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

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.