Double Free Vulnerability in FrankenPHP Affects PHP Applications
CVE-2026-128017

6.3MEDIUM

Key Information:

Vendor

PHP
Status
FrankenPHP
Vendor
CVE Published:
13 November 2026

What is CVE-2026-128017?

FrankenPHP prior to version 1.13.4 is susceptible to a double free vulnerability in its worker mode. This flaw occurs when the application frees the SG(request_info).content_type_dup variable twice after a non-form POST request is processed. Attackers not requiring authentication can exploit this by sending repeated JSON POST requests, ultimately causing the worker loop to terminate incorrectly when the USE_ZEND_ALLOC is set to 0. This vulnerability poses a risk to PHP applications utilizing FrankenPHP.

Affected Version(s)

frankenphp 0 < 1.13.4

frankenphp 1.13.4

References

https://github.com/php/frankenphp/security/advisories/GHS...
vendor-advisory
https://github.com/php/frankenphp/commit/8777cc2e5c872ebb...
patch
https://www.vulncheck.com/advisories/frankenphp-before-1....
third-party-advisory

CVSS V4

Score:
6.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
Low
Attack Vector:
Network
Attack Complexity:
High
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

atarus-security
.