Twisted vulnerable to NameVirtualHost Host header injection

CVE-2022-39348 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

Description

When the host header does not match a configured host, twisted.web.vhost.NameVirtualHost will return a NoResource resource which renders the Host header unescaped into the 404 response allowing HTML and script injection.

Example configuration:

from twisted.web.server import Site
from twisted.web.vhost import NameVirtualHost
from twisted.internet import reactor

resource = NameVirtualHost()
site = Site(resource)
reactor.listenTCP(8080, site)
reactor.run()

Output:

❯ curl -H"Host:<h1>HELLO THERE</h1>" http://localhost:8080/

<html>
  <head><title>404 - No Such Resource</title></head>
  <body>
    <h1>No Such Resource</h1>
    <p>host b'<h1>hello there</h1>' not in vhost map</p>
  </body>
</html>

This vulnerability was introduced in f49041bb67792506d85aeda9cf6157e92f8048f4 and first appeared in the 0.9.4 release.

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2022-10-26 22:08:39 UTC
Updated
2025-11-04 16:39:49 UTC
GitHub reviewed
2022-10-26 22:08:39 UTC
NVD published
2022-10-26

EPSS Score

Score Percentile
1.14% 78.36%

CVSS Scores

Base score Version Severity Vector
5.4 3.1 —
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
5.1 4.0 —
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:N)
No additional preconditions are required beyond normal reachability.
Privileges required (PR:L)
Low privileges are required.
User interaction (UI:P)
A user has to participate (for example click/open/approve).
Vulnerable system confidentiality impact (VC:N)
No confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:N)
No integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:N)
No availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:L)
Limited confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:L)
Limited integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.

Identifiers

Type Value
GHSA GHSA-vg46-2rrj-3647 ↗
CVE CVE-2022-39348 ↗

CWEs

CWE id Name
CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-80 Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)

Credits

  • westonsteimel (analyst)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
pip twisted >= 0.9.4, < 22.10.0rc1 22.10.0rc1 —

References

cvelogic Threat Intelligence