Account takeover via missing OAuth state validation
Published Jun 12, 2026 · Updated Jun 12, 2026
CSRF in phpBB 3.3.0 through 3.3.16 allows attackers to take over a logged-in user's account through a crafted OAuth account-link URL. OAuth service callers omit the state value, and the GET account-link endpoint redeems the attacker's authorization code without a CSRF check, binding that identity to the victim's session. OAuth must be configured and the victim must be logged in and load the URL; the attacker can then sign in through the linked identity as the victim.
Summary
What happened
CSRF in phpBB 3.3.0 through 3.3.16 allows attackers to take over a logged-in user's account through a crafted OAuth account-link URL. OAuth service callers omit the state value, and the GET account-link endpoint redeems the attacker's authorization code without a CSRF check, binding that identity to the victim's session. OAuth must be configured and the victim must be logged in and load the URL; the attacker can then sign in through the linked identity as the victim.
The record
- CVE
- CVE-2026-48612
- Published
- Jun 12, 2026
- Updated
- Jun 12, 2026
- Vendor
- phpBB
- Product
- phpBB
- Classifications
- CWE-352, T1078
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 12, 2026CVE publishedPublication date reported by the CVE source.
- Jun 12, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=3.3.0 <=3.3.16
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- OAuth auth-link account-takeover proof of conceptfunctional · demonstrated
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Technologies
Your stack
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Your stack
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