CVE-2023-27522: Apache HTTP Server: mod_proxy_uwsgi HTTP response splitting

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-03-07 · updated 2026-06-17
Weakness: CWE-444

Description

HTTP Response Smuggling vulnerability in Apache HTTP Server via mod_proxy_uwsgi. This issue affects Apache HTTP Server: from 2.4.30 through 2.4.55. Special characters in the origin response header can truncate/split the response forwarded to the client.

Affected products

Apache HTTP Server: from 2.4.30 before 2.4.56 — fixed in 2.4.56
Debian Linux: 10.0
Unbit Uwsgi: before 2.0.22 — fixed in 2.0.22

How to fix

Upgrade to a fixed version: Apache HTTP Server 2.4.56; Unbit Uwsgi 2.0.22. Check the vendor advisory for mitigations.

References

https://httpd.apache.org/security/vulnerabilities_24.html
https://lists.debian.org/debian-lts-announce/2023/04/msg00028.html
https://security.gentoo.org/glsa/202309-01
https://httpd.apache.org/security/vulnerabilities_24.html
https://lists.debian.org/debian-lts-announce/2023/04/msg00028.html
https://security.gentoo.org/glsa/202309-01

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