GHSA-hj8m-9fhf-v7jp: Fief server Fief-server Server-Side Template Injection Vulnerability Vulnerability

CRITICAL
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CVSS 10.0
Published
Advisory Summary

GHSA-hj8m-9fhf-v7jp is a CRITICAL (CVSS 10.0) fief-server server-side template injection vulnerability vulnerability (General Security Weakness) affecting Fief server libraries in the PyPI ecosystem. The issue involves fief-server server-side template injection vulnerability. Remediation is available by upgrading affected packages to version 0.25.3.

GHSA-hj8m-9fhf-v7jp at a Glance

CVE Identifier N/A
GHSA Identifier GHSA-hj8m-9fhf-v7jp
Severity CRITICAL
CVSS v3.1 Base Score 10.0
CWE Classification General Security Weakness
Affected Product Fief server
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 10.0

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Changed (S:C)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix GHSA-hj8m-9fhf-v7jp

To remediate this vulnerability, upgrade all affected Fief server dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

fief-server fixed: 0.25.3 
pip install fief-server>=0.25.3
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show fief-server

How to Check if You Are Affected

To determine whether your Python environment is affected by GHSA-hj8m-9fhf-v7jp, inspect your installed packages using pip:

pip show fief-server

Analyze the terminal output to locate any version of Fief server in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.25.3), your application is affected.

Note: The pip show fief-server command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under General Security Weakness. In Fief server, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

# Server-Side Template Injection ## Overview of the Vulnerability Server-Side Template Injection (SSTI) is a vulnerability within application templating engines where user input is improperly handled and is embedded into the template, possibly leading code being executed. An attacker can use SSTI to execute code on the underlying system by manipulating values within the embedded template. When code is executed within the underlying system, it can allow an attacker to run permissioned commands under the exploited process, or exploit Cross-Site Scripting (XSS) to run code within the user's browser. ## Business Impact SSTI can lead to reputational damage for the business due to a loss in confidence and trust by users. If an attacker successfully executes code within the underlying system, it can result in data theft and indirect financial losses. ## Steps to Reproduce 1. [Sign up](https://fief.fief.dev/register) and login to your account 1. Use a browser to navigate to: email-templates {{[URL](https://test.fief.dev/admin/customization/email-templates/)}} 1. put your payload in Edit Base template `{{ cycler.__init__.__globals__.os.popen('id').read() }}` and you will se it will execute. Payload: `{{ cycler.__init__.__globals__.os.popen('id').read() }}` ## Proof of Concept (PoC) The screenshot(s) below demonstrates the SSTI: ![SSTI](https://user-images.githubusercontent.com/42150485/248214990-854c2272-4f34-4c49-9759-d49ce8ce3d12.png)

GHSA-hj8m-9fhf-v7jp Affected Fief server Versions

1 component(s)
Fixed Versions:
0.25.3
Product / Package Ecosystem Affected Versions Fixed Version
fief-server
pypi/fief-server
PyPI
≥ 0.19.0
< 0.25.3
0.25.3

References

GitHub Advisory / Wiki ADVISORY
https://github.com/fief-dev/fief/security/advisories/GHSA-hj8m-9fhf-v7jp
Security Fix Commit FIX COMMIT
https://github.com/fief-dev/fief/commit/91e56625b641fa419e2985772266774bae18382b
Fief server Source Repository REPOSITORY
https://github.com/fief-dev/fief
Fief server Release RELEASE
https://github.com/fief-dev/fief/releases/tag/v0.25.3

Frequently Asked Questions

What is GHSA-hj8m-9fhf-v7jp?
GHSA-hj8m-9fhf-v7jp is a security vulnerability in Fief server involving fief-server Server-Side Template Injection vulnerability under General Security Weakness.
Which Fief server versions are affected?
Affected versions include releases prior to 0.25.3 across affected packages: fief-server.
What version fixes GHSA-hj8m-9fhf-v7jp?
Upgrading to 0.25.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is fief-server affected?
Yes, fief-server is affected in releases prior to 0.25.3. Upgrade your dependency to 0.25.3 or later.
What is the CVSS score of GHSA-hj8m-9fhf-v7jp?
GHSA-hj8m-9fhf-v7jp has a CVSS v3.1 base score of 10.0 (CRITICAL) with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.
What CWE is associated with GHSA-hj8m-9fhf-v7jp?
GHSA-hj8m-9fhf-v7jp is classified under General Security Weakness.
How can I check PyPI dependencies for GHSA-hj8m-9fhf-v7jp?
Run the dependency tree command: 'pip show fief-server'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-hj8m-9fhf-v7jp",
  "modified" : "2026-09-02T22:04:40Z",
  "published" : "2023-06-23T21:46:11Z",
  "aliases" : [ ],
  "summary" : "fief-server Server-Side Template Injection vulnerability",
  "details" : "# Server-Side Template Injection\n\n## Overview of the Vulnerability\n\nServer-Side Template Injection (SSTI) is a vulnerability within application templating engines where user input is improperly handled and is embedded into the template, possibly leading code being executed.\n\nAn attacker can use SSTI to execute code on the underlying system by manipulating values within the embedded template. When code is executed within the underlying system, it can allow an attacker to run permissioned commands under the exploited process, or exploit Cross-Site Scripting (XSS) to run code within the user's browser.\n\n## Business Impact\n\nSSTI can lead to reputational damage for the business due to a loss in confidence and trust by users. If an attacker successfully executes code within the underlying system, it can result in data theft and indirect financial losses.\n\n## Steps to Reproduce\n\n1. [Sign up](https://fief.fief.dev/register) and login to your account\n1. Use a browser to navigate to: email-templates {{[URL](https://test.fief.dev/admin/customization/email-templates/)}}\n1. put your payload in Edit Base template `{{ cycler.__init__.__globals__.os.popen('id').read() }}` and you will se it will execute.\n\nPayload:\n`{{ cycler.__init__.__globals__.os.popen('id').read() }}`\n\n## Proof of Concept (PoC)\n\nThe screenshot(s) below demonstrates the SSTI:\n\n![SSTI](https://user-images.githubusercontent.com/42150485/248214990-854c2272-4f34-4c49-9759-d49ce8ce3d12.png)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "fief-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.19.0"
      }, {
        "fixed" : "0.25.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/fief-dev/fief/security/advisories/GHSA-hj8m-9fhf-v7jp"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fief-dev/fief/commit/91e56625b641fa419e2985772266774bae18382b"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/fief-dev/fief"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fief-dev/fief/releases/tag/v0.25.3"
  } ],
  "database_specific" : {
    "cwe_ids" : [ ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-06-23T21:46:11Z",
    "nvd_published_at" : null
  }
}