Authentication Bypass Vulnerability in FrankenPHP by Wemi Technologies
CVE-2026-128023

9.1CRITICAL

Key Information:

Vendor

PHP
Status
FrankenPHP
Vendor
CVE Published:
13 November 2026

What is CVE-2026-128023?

FrankenPHP prior to version 1.13.0 is susceptible to an authentication bypass, enabling unauthenticated adversaries to spoof trusted headers. This vulnerability arises from the improper handling of dot-form header names, which PHP then rewrites into underscores. Attackers can exploit this weakness by crafting headers such as X.Authenticated.User or X.Forwarded.For, resulting in the manipulation of key server variables like user identity or client IP address. Such an exploit poses significant risks by allowing unauthorized access and control over server resources.

Affected Version(s)

frankenphp 0 < 1.13.0

frankenphp 1.13.0

References

https://github.com/php/frankenphp/security/advisories/GHS...
vendor-advisory
https://www.vulncheck.com/advisories/frankenphp-before-1....
third-party-advisory

CVSS V4

Score:
9.1
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

tikipiya
.