Skip to content
Fencer Vulns
medium 5.0

CVE-2023-23943 json

Blind SSRF via server URL input in the Nextcloud Mail app

published 2023-02-06 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-28009

cvss
5.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 60%
public exploits
0
none known

Summary

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.

Patch / fix

  • nextcloud mail 1.15.0, 2.2.2

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
19 mo ago

Exploit prediction

0.92% chance of exploitation in the next 30 days, higher than 60% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • hackerone.com https://hackerone.com/reports/1736390 referenced PoC, tagged "exploit" by a source, unverified
  • hackerone.com https://hackerone.com/reports/1741525 referenced PoC, tagged "exploit" by a source, unverified
  • hackerone.com https://hackerone.com/reports/1746582 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.0 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N
NVD 3.1 4.3 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected products

  • nextcloud security-advisories

Classification

Weakness
  • CWE-918 Server-Side Request Forgery

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.