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CVE-2026-6409

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

Published: Apr 16, 2026Updated: Apr 17, 2026 Sources: CVE List NVD BDUCWE-20
NVD MITRE
7.5CVSSHIGH
EPSS Score
0.4%
Top 72.4%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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 Vector Breakdown

AV:NAC:LC:NI:NA:H
Exploitability
AV:NAccess Vector
Network
AC:LAccess Complexity
Low
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
H
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Weaknesses

CWE-20

Affected Products

Protobuf-php (Pecl)Protocol Buffers
Library
OSS Libraries / generic-library
ProtobufGoogle Inc
On-prem
Mobile Apps / android-app
protocol buffersoss-projectOSS Librariesaka protocol-buffer, protocolbuffers, google protocol buffers
google inccommercialUSMobile Appsaka google

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available

MITRE ATT&CK

1 technique
Initial Access
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References

https://github.com/protocolbuffers/protobuf/security/advisories/GHSA-p2gh-cfq4-4wjc
github.com
https://github.com/protocolbuffers/protobuf/issues/25067
github.com

Timeline

Published
Apr 16, 2026
Last Updated
Apr 17, 2026

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