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CVE-2026-45691: Nextcloud is an open source content collaboration platform

26
Routine
MEDIUM 5.9UPGRADE

CVE-2026-45691 is a medium-severity flaw (CVSS 5.9) affecting nextcloud server. 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. In Nextcloud Server from versions 32.0.0 to before 32.0.9, and 33.0.0 to before 33.0.3, a pre-2FA session cookie (created after successful password authentication but before TOTP completion) could be reused as a Bearer token to authenticate against DAV endpoints, granting read/write access and bypassing mandatory two-factor authentication. It is recommended that the Nextcloud Server is u

Why this priority

  • No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score5.9 (Medium)
Attack vectorNetwork (remote)
Attack complexityHigh
Privileges neededLow
User interactionNone
EPSS exploit chance0.3% (top 79%)
CISA exploited listNo
WeaknessCWE-287
Published2026-06-01
Last modified2026-07-22
Publisher (CNA): GitHub, Inc. · Vendor: nextcloud

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Last updated 2026-07-22 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

nextcloud nextcloud server UPGRADE
Affected: >= 32.0.0 and < 32.0.9 · >= 33.0.0 and < 33.0.3 · >= 29.0.0 and < 29.0.16.16 · >= 30.0.0 and < 30.0.17.9 · >= 31.0.0 and < 31.0.14.5
Fixed in: 29.0.16.16, 30.0.17.9, 31.0.14.5, 32.0.9, 33.0.3
Safe to downgrade to: a release before 29.0.0
1. Check installed version
apt-cache policy nextcloud-server || rpm -q nextcloud-server || nextcloud-server --version
2. UPGRADE to 29.0.16.16 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade nextcloud-server
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade nextcloud-server
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 29.0.0 (Debian / Ubuntu)
apt-cache madison nextcloud-server sudo apt install nextcloud-server=<VERSION_BEFORE_29.0.0> sudo apt-mark hold nextcloud-server
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list nextcloud-server sudo dnf downgrade nextcloud-server-<VERSION_BEFORE_29.0.0> sudo dnf versionlock add nextcloud-server
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-2026-45691?

nextcloud server: upgrade to 29.0.16.16, 30.0.17.9, 31.0.14.5, 32.0.9, 33.0.3. Exact commands for each OS are on this page.

Is CVE-2026-45691 being exploited?

CVE-2026-45691 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-2026-45691 affect?

CVE-2026-45691 affects nextcloud server. Severity is medium (CVSS 5.9). Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 32.0.0 to before 32.0.9, and 33.0.0 to before 33.0.3, a pre-2FA session cookie (created after successful password authentication but before TOTP c

How urgent is CVE-2026-45691?

Priority 26/100. No elevated risk signals yet.

Software pages

Nextcloud vulnerabilities

Related CVEs

References

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