CVE-2026-45278

Description

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. This issue has been patched in version 8.2.2.

CVSS v3.1 Score

3.3

LOW

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

EPSS — Exploit Prediction

0.0023

Probability of exploitation

0.14%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-601 CWE-601

Affected Products

Vendor	Product	Versions
nextcloud	user_oidc	6.1.0 — 8.2.2

References

Advisories & Patches

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-8wjr-5cg8-4w73 https://github.com/nextcloud/user_oidc/pull/1273

Other References

https://hackerone.com/reports/3464925

Frequently Asked Questions

What is CVE-2026-45278? +

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. This issue has been patched in version 8.2.2. It has a CVSS v3.1 base score of 3.3 (LOW).

How severe is CVE-2026-45278? +

CVE-2026-45278 has a CVSS v3.1 score of 3.3 out of 10, rated LOW. This is a low-severity vulnerability with limited impact. The EPSS score is 0.0023, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-45278? +

CVE-2026-45278 affects products from nextcloud, specifically: user_oidc. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-45278? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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