Vulnerability · Published May 4, 2026 · Assigned by hackerone
CVE-2026-29199
High 8.1
In plain English
A high-severity security flaw in phpBB from phpBB. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 16% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
phpBB before 3.3.16 is vulnerable to Host Header Injection that can lead to password rest link poisoning. When force_server_vars is disabled, the servers hostname may be extracted from the HTTP Host header which is used to generate the password reset link URL. An attacker who can manipulate the Host header (e.g. through misconfigured host setup or missing header validation by the webserver) can cause password reset emails to contain a link pointing to an attacker-controlled domain, potentially leading to account takeover.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Packagist | phpbb/phpbb | 3.3.16 | GHSA-7gm6-w7mx-58cr |
| Packagist | phpbb/phpbb | 4.0.0-a2 | GHSA-7gm6-w7mx-58cr |
Affected products (as reported)
Weakness: CWE-640 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N