CVE-2026-45278: Nextcloud is an open source content collaboration platform

Routine

LOW 3.3UPGRADE

CVE-2026-45278 is a low-severity flaw (CVSS 3.3) affecting user oidc. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	3.3 (Low)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.2% (top 86%)
CISA exploited list	No
Weakness	CWE-601
Published	2026-06-01
Last modified	2026-07-20

Publisher (CNA): GitHub, Inc. · Vendor: nextcloud

Last updated 2026-07-20 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-01 19:16 UTCPublished CVE record published
2026-07-20 20:10 UTCUpdated Record last modified

nextcloud user oidc UPGRADE

Affected: >= 6.1.0 and < 8.2.2

Fixed in: 8.2.2

Safe to downgrade to: a release before 6.1.0

1. Check installed version

apt-cache policy user-oidc || rpm -q user-oidc || user-oidc --version

2. UPGRADE to 8.2.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade user-oidc

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade user-oidc

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 6.1.0 (Debian / Ubuntu)

apt-cache madison user-oidc sudo apt install user-oidc=<VERSION_BEFORE_6.1.0> sudo apt-mark hold user-oidc

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list user-oidc sudo dnf downgrade user-oidc-<VERSION_BEFORE_6.1.0> sudo dnf versionlock add user-oidc

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-45278?

user oidc: upgrade to 8.2.2. Exact commands for each OS are on this page.

Is CVE-2026-45278 being exploited?

CVE-2026-45278 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-45278 affect?

CVE-2026-45278 affects user oidc. Severity is low (CVSS 3.3). 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 OID

How urgent is CVE-2026-45278?

Priority 15/100. No elevated risk signals yet.

Software pages

Nextcloud vulnerabilities

Related CVEs

CVE-2026-45284 MEDIUM 4.6 UPGRADE Nextcloud is an open source content collaboration platform

References

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