Cyber Resilience

CVE-2026-45278

Open Redirect in Nextcloud User Oidc 6.1.0 – 8.2.2

Open Redirect
Published
01 June 2026
Modified
20 July 2026
Patch / advisory
View advisory
CVSS Score v3.1 3.3
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
EPSS Score 0.0023 14th percentile
Risk Priority 29 floored blend · peak EPSS

Summary

CVE-2026-45278 is a low-severity Open Redirect (CWE-601) vulnerability in Nextcloud User Oidc. Its CVSS base score is 3.3 (Low).

Operationally, exploitation aligns with the MITRE ATT&CK technique Phishing (T1566); ranked at the 14th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and AC-4 (Information Flow Enforcement) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability Data

Nextcloud is an open source content collaboration platform. From version 6.1.0 to before version 8.2.2, an attacker can craft links that would redirect users to another website, when the victim uses the attackers link to log in via user OIDC.…

more

This issue has been patched in version 8.2.2.

CWE(s)
CWE-601

Related Threats

MITRE ATT&CK Enterprise Techniques

T1566 Phishing Initial Access
Adversaries may send phishing messages to gain access to victim systems.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-52512Same product: Nextcloud User Oidc
CVE-2023-35171Same vendor: Nextcloud
CVE-2023-28848Same product: Nextcloud User Oidc
CVE-2023-32074Same product: Nextcloud User Oidc
CVE-2023-39954Same product: Nextcloud User Oidc
CVE-2024-22400Same vendor: Nextcloud
CVE-2023-39953Same product: Nextcloud User Oidc
CVE-2024-37886Same product: Nextcloud User Oidc
CVE-2024-37312Same product: Nextcloud User Oidc
CVE-2026-45284Same product: Nextcloud User Oidc

Affected Assets

nextcloud
user oidc
6.1.0 — 8.2.2

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V3.7.2

Mitigating Controls (NIST 800-53 r5) AI

SI-10 Information Input Validation good match

Input validation directly checks and rejects untrusted redirect targets before they are used in a response.

AC-4 Information Flow Enforcement partial match

Information flow enforcement can restrict redirects to only approved/trusted destinations, stopping untrusted user-supplied URLs from being followed.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require input validation and untrusted-redirect controls that prevent CWE-601.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.23 Web filtering partial match
mitigates

Preventing access to attacker-controlled or malicious sites stops users from being redirected to untrusted locations via open-redirect or phishing links.

References