# CVE-2026-109163: Apache HTTP Server mod_vhost_alias stack buffer overflow

Source: https://junglewise.ai/threats/cve-2026-109163-stack-based-buffer-overflow-vulnerability-in-apache-http-server  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-11. Updated: 2026-11-11  
License: CC BY 4.0 with a link back

CVE-2026-109163 · Severity: info · Published 2026-11-11

Apache HTTP Server's mod_vhost_alias module, used to dynamically configure virtual hosts, contains a stack-based buffer overflow vulnerability that allows a remote attacker to overwrite one byte of stack memory. An attacker can exploit this to crash the server or potentially execute arbitrary code on systems running affected versions.

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

## Quick answers

**Is CVE-2026-109163 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-109163 being exploited in the wild.

**How severe is CVE-2026-109163?** Informational severity, published 11 November 2026.

**Which products and versions are affected?** Apache HTTP Server 2.4.69, 2.4.70.

**Is there a fix for CVE-2026-109163?** Yes: fixed in Apache HTTP Server 2.4.71. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-109163 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-109163?** 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 2.4.71

## Technical details

A stack-based buffer overflow in mod_vhost_alias allows writing one byte beyond a stack buffer. The vulnerability is triggered when processing HTTP requests with specially crafted Host headers on a system where VirtualDocumentRoot uses a hostname format specifier. No authentication or user interaction is required; the attack is network-accessible.

## Affected products

- Apache HTTP Server 2.4.69, 2.4.70

## Timeline

- 2026-11-11: disclosed
- 2026-11-11: patched: Apache HTTP Server 2.4.71 released

## References

- [https://httpd.apache.org/security/vulnerabilities_24.html](https://httpd.apache.org/security/vulnerabilities_24.html)

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