High severity · published Oct 23, 2026
CVE-2026-87901
Improper sanitization in the registration module allows reflected Cross-Site Scripting
New
8.3
CVSS
0.3%
EPSS
No
On KEV
Description
Improper sanitization in the registration module allows reflected Cross-Site Scripting.
CVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
High
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 21% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PH
phpBB · phpBB
3.3.0 through 3.3.18 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-87901
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-87901
www.phpbb.com
https://www.phpbb.com/community/viewtopic.php?t=2675305
More from phpBB
9.8
CVE-2026-48611
Improper authentication checks in the OAuth implementation allow account hijacking even when OAuth is not configured or enabled leading to unauthorized access in default…
8.8
CVE-2025-70810
Cross Site Request Forgery vulnerability in Phpbb phbb3 v.3.3.15 allows a local attacker to execute arbitrary code via the login function and the authentication mechanism
8.8
CVE-2019-16993
In phpBB before 3.1.7-PL1, includes/acp/acp_bbcodes.php has improper verification of a CSRF token on the BBCode page in the Administration Control Panel
8.8
CVE-2001-1471
prefs.php in phpBB 1.4.0 and earlier allows remote authenticated users to execute arbitrary PHP code via an invalid language value, which prevents the variables (1) $l_statsblock…
8.1
CVE-2026-29199
phpBB before 3.3.16 is vulnerable to Host Header Injection that can lead to password rest link poisoning