Critical severity · published Jun 12, 2026
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…
9.8
CVSS
3.9%
EPSS
No
On KEV
Description
Improper authentication checks in the OAuth implementation allow account hijacking even when OAuth is not configured or enabled leading to unauthorized access in default installations.
CVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)3.9% · higher than 90% 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 3.3.16 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-48611
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-48611
www.phpbb.com
https://www.phpbb.com/community/viewtopic.php?t=2672170
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