CVE-2023-39963: Missing password confirmation when creating app passwords

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-08-10 · updated 2026-06-17
Weakness: CWE-284

Description

Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. Starting in version 20.0.0 and prior to versions 20.0.14.15, 21.0.9.13, 22.2.10.14, 23.0.12.8, 24.0.12.5, 25.0.9, 26.0.4, and 27.0.1, a missing password confirmation allowed an attacker, after successfully stealing a session from a logged in user, to create app passwords for the victim. Nextcloud server versions 25.0.9, 26.0.4, and 27.0.1 and Nextcloud Enterprise Server versions 20.0.14.15, 21.0.9.13, 22.2.10.14, 23.0.12.9, 24.0.12.5, 25.0.9, 26.0.4, and 27.0.1 contain a patch for this issue. No known workarounds are available.

Affected products

Nextcloud Server: from 20.0.0 before 20.0.14.15; from 21.0.0 before 21.0.9.13; from 22.0.0 before 22.2.10.14; from 23.0.0 before 23.0.12.9; from 24.0.0 before 24.0.12.5; from 25.0.0 before 25.0.9 — fixed in 20.0.14.15, 21.0.9.13, 22.2.10.14, 23.0.12.9, 24.0.12.5, 25.0.9

How to fix

Upgrade to a fixed version: Nextcloud Server 20.0.14.15, 21.0.9.13, 22.2.10.14, 23.0.12.9. Check the vendor advisory for mitigations.

References

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