SecuriTricks - CVE-2026-45156

Description

Nextcloud is an open source content collaboration platform. From versions 0.3.0 to before 3.1.0, 5.0.0 to before 5.1.0, and 6.0.0 to before 6.4.0, a missing signature verification in User OIDC allowed a malicious ID4me authority to identify as any user. This issue has been patched in versions 3.1.0, 4.1.0, 5.1.0, 6.4.0 and 8.3.0.

Product(s) Impacted

Vendor	Product	Versions
Nextcloud	Nextcloud	0.3.0-3.1.0, 5.0.0-5.1.0, 6.0.0-6.4.0, 3.1.0, 4.1.0, 5.1.0, 6.4.0, 8.3.0

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-287

Improper Authentication

When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

*CPE(s)

Affected systems and software identified for this CVE.

Type	Vendor	Product	Version	Update	Edition	Language	Software Edition	Target Software	Target Hardware	Other Information
a	nextcloud	nextcloud	0.3.0-3.1.0	/	/	/	/	/	/	/
a	nextcloud	nextcloud	5.0.0-5.1.0	/	/	/	/	/	/	/
a	nextcloud	nextcloud	6.0.0-6.4.0	/	/	/	/	/	/	/
a	nextcloud	nextcloud	3.1.0	/	/	/	/	/	/	/
a	nextcloud	nextcloud	4.1.0	/	/	/	/	/	/	/
a	nextcloud	nextcloud	5.1.0	/	/	/	/	/	/	/
a	nextcloud	nextcloud	6.4.0	/	/	/	/	/	/	/
a	nextcloud	nextcloud	8.3.0	/	/	/	/	/	/	/

References

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-qqgv-fqwp-mjpp

https://github.com/nextcloud/user_oidc/pull/1285

https://hackerone.com/reports/3489490

CVSS Score

8.1 / 10

CVSS Data - 3.1

Attack Vector: NETWORK
Attack Complexity: LOW
Privileges Required: NONE
Scope: UNCHANGED
Confidentiality Impact: HIGH
Integrity Impact: HIGH
Availability Impact: NONE

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

View Vector String

Timeline

Published: June 1, 2026, 5:17 p.m.
Last Modified: June 1, 2026, 6:14 p.m.

Status : Deferred

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

[email protected]

CVE-2026-45156