CVE-2026-45279: Nextcloud: Limited path traversal via template API if using `{lang}` in config

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-01 · updated 2026-07-22
Weakness: CWE-22

Description

Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 31.0.0 to before 31.0.14, and 32.0.0 to before 32.0.4, if {lang} is used in the template directory config value, non-admin users can in some cases copy arbitrary files (depending on unix permissions) into their own Nextcloud directory via a path traversal. It is recommended that the Nextcloud Server is upgraded to 32.0.4, 31.0.14. It is recommended that the Nextcloud Enterprise Server is upgraded to 32.0.4, 31.0.14, 30.0.17.7, 29.0.17.12, 28.0.14.15

Affected products

Nextcloud Server: from 31.0.0 before 31.0.14; from 32.0.0 before 32.0.4; from 28.0.0 before 28.0.14.15; from 29.0.0 before 29.0.17.12; from 30.0.0 before 30.0.17.7 — fixed in 28.0.14.15, 29.0.17.12, 30.0.17.7, 31.0.14, 32.0.4

How to fix

Upgrade to a fixed version: Nextcloud Server 28.0.14.15, 29.0.17.12, 30.0.17.7, 31.0.14. Check the vendor advisory for mitigations.

References

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