# CVE-2026-29199: phpBB Host Header Injection in password reset mechanism

Source: https://junglewise.ai/threats/cve-2026-29199-phpbb-host-header-injection-in-password-reset-mechanism  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-04. Updated: 2026-06-18  
License: CC BY 4.0 with a link back

CVE-2026-29199 · Severity: high · CVSS 8.1 · Published 2026-05-04

phpBB, a popular open-source forum software, is vulnerable to a flaw that allows attackers to manipulate password reset emails. By tricking the system into using a malicious web address, an attacker can send a legitimate-looking password reset link to a user that actually directs them to a site controlled by the attacker. If a user clicks this link, the attacker can capture their credentials and take over their account.

Technologies: [phpbb/phpbb (Packagist)](https://junglewise.ai/threats/technologies/phpbb-phpbb), [Phpbb](https://junglewise.ai/threats/technologies/phpbb). Vendors: [Packagist](https://junglewise.ai/threats/vendors/packagist), [Phpbb](https://junglewise.ai/threats/vendors/phpbb).

## Quick answers

**Is CVE-2026-29199 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-29199 being exploited in the wild.

**How severe is CVE-2026-29199?** High severity, with a CVSS score of 8.1, published 4 May 2026.

**Which products and versions are affected?** phpbb/phpbb (Packagist) ECOSYSTEM:introduced=3.0.0,fixed=3.3.16.

**Is there a fix for CVE-2026-29199?** Yes. phpbb/phpbb (Packagist): upgrade to 3.3.16 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-29199 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-29199?** Check whether you run phpbb/phpbb (Packagist) or Phpbb 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

- phpbb/phpbb (Packagist): upgrade to 3.3.16 or later

  ```sh
  composer require phpbb/phpbb:^3.3.16
  ```


## Technical details

phpBB before 3.3.16 and version 4.0.0-a1 are vulnerable to Host Header Injection (CWE-640). When the 'force_server_vars' configuration is disabled, the application may use the HTTP Host header provided by the client to generate absolute URLs for password reset emails. An attacker can provide a malicious Host header during a password reset request; if the web server does not validate this header, the resulting email will contain a reset link pointing to an attacker-controlled domain. This allows the attacker to intercept the reset token when the victim clicks the link, leading to account takeover. The issue is patched in versions 3.3.16 and 4.0.0-a2.

## Affected products

- phpBB phpBB >= 3.0.0, < 3.3.16; 4.0.0-a1

## Identifiers

- CVE-2026-29199
- GHSA-7gm6-w7mx-58cr

## Timeline

- 2026-04-27: patched: Patch released in version 4.0.0-a2
- 2026-05-04: disclosed
- 2026-05-04: advisory

## References

- [https://api.github.com/users/marc1706](https://api.github.com/users/marc1706)
- [https://github.com/marc1706](https://github.com/marc1706)
- [https://api.github.com/users/marc1706/gists%7B/gist_id%7D](https://api.github.com/users/marc1706/gists%7B/gist_id%7D)
- [https://api.github.com/users/marc1706/repos](https://api.github.com/users/marc1706/repos)
- [https://avatars.githubusercontent.com/u/394418?v=4](https://avatars.githubusercontent.com/u/394418?v=4)
- [https://api.github.com/users/marc1706/events%7B/privacy%7D](https://api.github.com/users/marc1706/events%7B/privacy%7D)

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