CVE-2021-29659: ownCloud 10.7 has an incorrect access control vulnerability, leading to remote information disclosure

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MEDIUM 6.5DOWNGRADE

CVE-2021-29659 is a medium-severity flaw (CVSS 6.5) affecting owncloud server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

ownCloud 10.7 has an incorrect access control vulnerability, leading to remote information disclosure. Due to a bug in the related API endpoint, the attacker can enumerate all users in a single request by entering three whitespaces. Secondary, the retrieval of all users on a large instance could cause higher than average load on the instance.

Why this priority

No elevated risk signals yet

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	1.3% (top 29%)
CISA exploited list	No
Published	2021-05-20
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: owncloud

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-05-20 13:15 UTCPublished CVE record published
2026-06-17 03:48 UTCUpdated Record last modified

owncloud owncloud server DOWNGRADE

Affected: 10.7.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 10.7.0

1. Check installed version

apt-cache policy owncloud-server || rpm -q owncloud-server || owncloud-server --version

2. No fixed release: DOWNGRADE to a release before 10.7.0 (Debian / Ubuntu)

apt-cache madison owncloud-server sudo apt install owncloud-server=<VERSION_BEFORE_10.7.0> sudo apt-mark hold owncloud-server

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list owncloud-server sudo dnf downgrade owncloud-server-<VERSION_BEFORE_10.7.0> sudo dnf versionlock add owncloud-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-2021-29659?

owncloud server: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-29659 being exploited?

CVE-2021-29659 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-2021-29659 affect?

CVE-2021-29659 affects owncloud server. Severity is medium (CVSS 6.5). ownCloud 10.7 has an incorrect access control vulnerability, leading to remote information disclosure. Due to a bug in the related API endpoint, the attacker can enumerate all users in a single request by entering three whitespaces. Seconda

How urgent is CVE-2021-29659?

Priority 40/100. No elevated risk signals yet.

Software pages

ownCloud vulnerabilities

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References

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