CVE-2022-2255Network attack vector

Client IP spoofing via missing header check

Published Aug 25, 2022 · Updated Aug 3, 2024

Improper header validation in mod_wsgi before 4.9.3 allows remote attackers to spoof X-Client-IP values passed to WSGI applications. The wsgi_process_proxy_headers function omits HTTP_X_CLIENT_IP from the trusted-header comparison, so an untrusted request retains the supplied value. Exploitation requires a deployment that trusts X-Client-IP through WSGITrustedProxies and WSGITrustedProxyHeaders; downstream applications can then make security decisions using a forged client address.

CVSS severity8.7
High
EPSS probability0.88%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper header validation in mod_wsgi before 4.9.3 allows remote attackers to spoof X-Client-IP values passed to WSGI applications. The wsgi_process_proxy_headers function omits HTTP_X_CLIENT_IP from the trusted-header comparison, so an untrusted request retains the supplied value. Exploitation requires a deployment that trusts X-Client-IP through WSGITrustedProxies and WSGITrustedProxyHeaders; downstream applications can then make security decisions using a forged client address.

The record

CVE
CVE-2022-2255
Published
Aug 25, 2022
Updated
Aug 3, 2024
Vendor
Graham Dumpleton
Product
mod_wsgi
Classifications
CWE-345
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 25, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=mod_wsgi versions prior to 4.9.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Graham Dumpleton · mod_wsgiversion=mod_wsgi versions prior to 4.9.3

Published CVSS scores

8.7GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-345Insufficient Verification of Data Authenticity

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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