#VU83565 Improper access control in oauth2 - CVE-2023-49104

Vulnerability identifier: #VU83565

Vulnerability risk: Medium

CVSSv4.0: 6.9 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2023-49104

CWE-ID: CWE-284

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
oauth2
Universal components / Libraries / Programming Languages & Components

Vendor: ownCloud

Description

The vulnerability allows a remote attacker to bypass subdomain validation.

The vulnerability exists due to improper access restrictions when Allow Subdomains is enabled. A remote attacker can pass in a specially crafted redirect-url which bypasses the validation code and thus allows the attacker to redirect callbacks to a TLD controlled by the attacker.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

oauth2: 0.1.0 - 0.6.0

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External links
https://owncloud.com/security-advisories/subdomain-validation-bypass/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.