Response smuggling via unvalidated uWSGI response headers
Published Mar 7, 2023 · Updated Feb 13, 2025
HTTP response smuggling in Apache HTTP Server 2.4.30 through 2.4.55 allows remote attackers to alter client responses via mod_proxy_uwsgi. The uwsgi_response parser adds backend header names and values to headers_out without rejecting invalid tokens or field content, so special characters can truncate or split the forwarded response. Exploitation requires mod_proxy_uwsgi to proxy a UWSGI backend whose response headers contain attacker-controlled special characters; the bounded impact is modification of responses delivered to clients.
Summary
What happened
HTTP response smuggling in Apache HTTP Server 2.4.30 through 2.4.55 allows remote attackers to alter client responses via mod_proxy_uwsgi. The uwsgi_response parser adds backend header names and values to headers_out without rejecting invalid tokens or field content, so special characters can truncate or split the forwarded response. Exploitation requires mod_proxy_uwsgi to proxy a UWSGI backend whose response headers contain attacker-controlled special characters; the bounded impact is modification of responses delivered to clients.
The record
- CVE
- CVE-2023-27522
- Published
- Mar 7, 2023
- Updated
- Feb 13, 2025
- Vendor
- The Apache Software Foundation
- Product
- Apache HTTP Server
- Classifications
- CWE-444, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 7, 2023CVE publishedPublication date reported by the CVE source.
- Feb 13, 2025Record 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.
- Affected versionversion=2.4.30 <=2.4.55
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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