CVE-2023-23943

Blind SSRF via server URL input in the Nextcloud Mail app

5.0 Medium

Nextcloud mail is an email app for the nextcloud home server platform. In affected versions the SMTP, IMAP and Sieve host fields allowed to scan for internal services and servers reachable from within the local network of the Nextcloud Server. It is recommended that the Nextcloud Maill app is upgraded to 1.15.0 or 2.2.2. The only known workaround for this issue is to completely disable the nextcloud mail app.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: Low
Integrity: None
Availability: None

Exploit likelihood

0.92%Unchanged since Feb 7, 2023

What each source reports

CVE List Score used 5.0

Blind SSRF via server URL input in the Nextcloud Mail app

Record: CVE-2023-23943
CVSS 3.1: 5.0 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N
Weakness: CWE-918
Updated: 2026-11-02

EUVDEUVD-2023-28009 5.0

Record: EUVD-2023-28009
CVSS 3.1: 5.0 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N
Updated: 2026-11-02

NVD 5.0

Record: CVE-2023-23943
CVSS 3.1: 5.0 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N
CVSS 3.1: 4.3 MediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Weakness: CWE-918
Updated: 2026-11-02

OSV 5.0

Blind SSRF via server URL input in the Nextcloud Mail app

Record: CVE-2023-23943
CVSS 3.1: 5.0 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N
Weakness: CWE-918
Updated: 2026-11-02

Affected products

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2023-23943 is a medium vulnerability (CVSS 5.0) in Nextcloud Mail, published February 6, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.92%, the 60th percentile. No source names a fixed version.