# CVE-2026-63718: Apache HTTP Server response smuggling in mod_proxy_uwsgi

Source: https://junglewise.ai/threats/cve-2026-63718-inconsistent-interpretation-of-http-requests-http-request  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-01. Updated: 2026-10-05  
License: CC BY 4.0 with a link back

CVE-2026-63718 · Severity: high · CVSS 7.5 · Published 2026-10-01

Apache HTTP Server, a widely-used web server that processes HTTP requests and proxies them to backend services, contains a response smuggling vulnerability in its mod_proxy_uwsgi module. An attacker can craft a malicious uwsgi response with Transfer-Encoding headers to cause the web server to misinterpret HTTP responses, potentially allowing cache poisoning or request smuggling attacks that could affect downstream systems or cached content.

Technologies: [Apache HTTP Server](https://junglewise.ai/threats/technologies/http-server). Vendors: [Apache](https://junglewise.ai/threats/vendors/apache).

## Quick answers

**Is CVE-2026-63718 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-63718 being exploited in the wild.

**How severe is CVE-2026-63718?** High severity, with a CVSS score of 7.5, published 1 October 2026.

**Which products and versions are affected?** Apache HTTP Server 2.4.30 through 2.4.68.

**Is there a fix for CVE-2026-63718?** Yes: fixed in Apache HTTP Server 2.4.69. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-63718 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-63718?** Check whether you run Apache HTTP Server at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in Apache HTTP Server 2.4.69

## Technical details

This HTTP response smuggling vulnerability exists in mod_proxy_uwsgi due to inconsistent interpretation of Transfer-Encoding headers in crafted uwsgi responses. The vulnerability affects Apache HTTP Server versions 2.4.30 through 2.4.68 and requires network access to a server with mod_proxy_uwsgi enabled proxying to a uWSGI backend. An attacker controlling or able to influence a proxied uWSGI application can inject crafted responses that bypass request/response boundary validation.

## Affected products

- Apache HTTP Server 2.4.30 through 2.4.68

## Timeline

- 2026-07-14: disclosed: Vulnerability reported to Apache security team
- 2026-10-01: patched: Fixed in 2.4.x by r1938691
- 2026-10-01: advisory: Apache HTTP Server 2.4.69 released

## References

- [https://httpd.apache.org/security/vulnerabilities_24.html](https://httpd.apache.org/security/vulnerabilities_24.html)
- [http://www.openwall.com/lists/oss-security/2026/10/01/26](http://www.openwall.com/lists/oss-security/2026/10/01/26)

## Related threats

- [Apache HTTP Server mod_http2 heap corruption in assign_headers](https://junglewise.ai/threats/cve-2026-119618-concurrent-execution-using-shared-resource-with-improper)
- [Apache HTTP Server mod_vhost_alias stack buffer overflow](https://junglewise.ai/threats/cve-2026-109163-stack-based-buffer-overflow-vulnerability-in-apache-http-server)
- [Apache HTTP Server mod_md NULL pointer dereference](https://junglewise.ai/threats/cve-2026-106023-null-pointer-dereference-vulnerability-in-apache-http-server-s)
- [Apache HTTP Server mod_dav_fs integer overflow in namespace handling](https://junglewise.ai/threats/cve-2026-93546-integer-overflow-in-mod-dav-fs-in-apache-http-server-through-2-4)
- [Apache HTTP Server mod_userdir path equivalence in single-dot directory](https://junglewise.ai/threats/cve-2026-79768-path-equivalence-single-dot-directory-vulnerability-in-apache)