High 8.1Published Jun 1, 2026

CVE-2026-45156Nextcloud: Authentication Bypass in ID4me handling via Missing JWT Signature Verification in User OIDC

Updated under an hour ago (Oct 26, 2026, 11:50 PM ET)

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It affects nextcloud security-advisories. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for nextcloud security-advisories

Exploited in the last 30 days

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.

CVSS: 8.1 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Weakness (CWE): CWE-287
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Jun 2, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

nextcloud security-advisories nextcloud:security_advisories (from the name)	from 0.3.0, < 3.1.0; from 5.0.0, < 5.1.0; from 6.0.0, < 6.4.0	CNA record

References

References

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-qqgv-fqwp-mjpp	x-refsource-confirm
https://github.com/nextcloud/user_oidc/pull/1285	x-refsource-misc
https://hackerone.com/reports/3489490	x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.