How severe is CVE-2023-27522?

CVE-2023-27522 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2023-27522 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-27522?

CVE-2023-27522 primarily affects Apache Http Server. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-27522?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2023-27522 published?

CVE-2023-27522 was published on 2023-03-07 and last updated on 2026-06-17.

CVE-2023-27522

CVE-2023-27522 is a high-severity vulnerability in Apache Http Server with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-444.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 2% (80th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-444
Affected product: Apache Http Server
Published: 2023-03-07
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2023-27522?: 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.
How severe is CVE-2023-27522?: CVE-2023-27522 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2023-27522 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-27522?: CVE-2023-27522 primarily affects Apache Http Server. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-27522?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2023-27522 published?: CVE-2023-27522 was published on 2023-03-07 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:a:unbit:uwsgi:*:*:*:*:*:*:*:*

More vulnerabilities in Apache Http Server

CVE-2010-0425 — Critical (CVSS 10.0): modules/arch/win32/mod_isapi.c in mod_isapi in the Apache HTTP Server 2.0.37 through 2.0.63, 2.2.0 through 2.2.14, and…
CVE-2005-2700 — Critical (CVSS 10.0): ssl_engine_kernel.c in mod_ssl before 2.8.24, when using "SSLVerifyClient optional" in the global virtual host…
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CVE-1999-1293 — Critical (CVSS 10.0): mod_proxy in Apache 1.2.5 and earlier allows remote attackers to cause a denial of service via malformed FTP commands,…
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All CVEs affecting Apache Http Server →

Other CWE-444 (HTTP Request/Response Smuggling) vulnerabilities

CVE-2025-1867 — Critical (CVSS 10.0): Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in ithewei libhv allows…
CVE-2022-22536 — Critical (CVSS 10.0): SAP NetWeaver Application Server ABAP, SAP NetWeaver Application Server Java, ABAP Platform, SAP Content Server 7.53…
CVE-2018-3907 — Critical (CVSS 10.0): An exploitable vulnerability exists in the REST parser of video-core's HTTP server of the Samsung SmartThings Hub…
CVE-2025-55315 — Critical (CVSS 9.9): Inconsistent interpretation of http requests ('http request/response smuggling') in ASP.NET Core allows an authorized…
CVE-2020-15049 — Critical (CVSS 9.9): An issue was discovered in http/ContentLengthInterpreter.cc in Squid before 4.12 and 5.x before 5.0.3. A Request…
CVE-2026-13763 — Critical (CVSS 9.8): Inconsistent interpretation of HTTP/2 requests in AWS Application Load Balancer with AWS WAF enabled might allow remote…

Browse all CWE-444 (HTTP Request/Response Smuggling) vulnerabilities →

Threat intelligence

Threat-intel indicators referencing this CVE:

50.255.62.89 (ipv4-addr)
46.253.45.10 (ipv4-addr)
45.187.108.43 (ipv4-addr)
41.89.227.164 (ipv4-addr)
41.128.181.199 (ipv4-addr)
34.18.62.244 (ipv4-addr)
223.197.186.7 (ipv4-addr)
218.51.148.194 (ipv4-addr)