CVE-2021-20281

Moodle allowed some users without permission to view other users' full names

5.3 MediumFix available

It was possible for some users without permission to view other users' full names to do so via the online users block in moodle before 3.10.2, 3.9.5, 3.8.8, 3.5.17.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: Low
Integrity: None
Availability: None

Exploit likelihood

1.36%Up 0.1 points since Apr 14, 2021

What each source reports

NVD Score used 5.3

It was possible for some users without permission to view other users' full names to do so via the online users block in moodle before 3.10.2, 3.9.5, 3.8.8, 3.5.17.

Record: CVE-2021-20281
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CVSS 2.0: 5.0 MediumAV:N/AC:L/Au:N/C:P/I:N/A:N
Weakness: CWE-200, CWE-863
Updated: 2026-11-02

CVE List No score

It was possible for some users without permission to view other users' full names to do so via the online users block in moodle before 3.10.2, 3.9.5, 3.8.8, 3.5.17.

Record: CVE-2021-20281
Weakness: CWE-200
Updated: 2026-11-02

EUVDEUVD-2021-0636 No score

It was possible for some users without permission to view other users' full names to do so via the online users block in moodle before 3.10.2, 3.9.5, 3.8.8, 3.5.17.

Record: EUVD-2021-0636
Updated: 2026-11-03

GitHub AdvisoriesGHSA-93wh-35r4-6qmw 5.3

Moodle allowed some users without permission to view other users' full names

It was possible for some users without permission to view other users' full names to do so via the online users block in moodle before 3.10.2, 3.9.5, 3.8.8, 3.5.17.

Record: GHSA-93wh-35r4-6qmw
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Weakness: CWE-200, CWE-863
Updated: 2026-11-02

OSV 5.3

It was possible for some users without permission to view other users' full names to do so via the online users block in moodle before 3.10.2, 3.9.5, 3.8.8, 3.5.17.

Record: CVE-2021-20281
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Updated: 2026-11-02

OSVGHSA-93wh-35r4-6qmw 5.3

Moodle allowed some users without permission to view other users' full names

It was possible for some users without permission to view other users' full names to do so via the online users block in moodle before 3.10.2, 3.9.5, 3.8.8, 3.5.17.

Record: GHSA-93wh-35r4-6qmw
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Weakness: CWE-200, CWE-863
Updated: 2026-11-02

OSVUBUNTU-CVE-2021-20281 5.3

It was possible for some users without permission to view other users' full names to do so via the online users block in moodle before 3.10.2, 3.9.5, 3.8.8, 3.5.17.

Record: UBUNTU-CVE-2021-20281
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Updated: 2026-11-02

OSVBIT-moodle-2021-20281 No score

It was possible for some users without permission to view other users' full names to do so via the online users block in moodle before 3.10.2, 3.9.5, 3.8.8, 3.5.17.

Record: BIT-moodle-2021-20281
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`moodle/moodle` Packagist	3.10.0 up to 3.10.2	3.10.2
`moodle/moodle` Packagist	3.9.0 up to 3.9.5	3.9.5
`moodle/moodle` Packagist	3.8.0 up to 3.8.8	3.8.8
`moodle/moodle` Packagist	3.5 up to 3.5.17	3.5.17
`moodle` Bitnami	3.5.0 up to 3.5.17, 3.8.0 up to 3.8.8, 3.9.0 up to 3.9.5, 3.10.0 up to 3.10.2	3.5.173.8.83.9.53.10.2
`moodle/moodle` Packagist	3.10.0 up to 3.10.2, plus listed versions v3.10.0v3.10.1	3.10.2
`moodle/moodle` Packagist	3.9.0 up to 3.9.5, plus listed versions v3.9.0v3.9.1v3.9.2v3.9.3v3.9.4	3.9.5
`moodle/moodle` Packagist	3.8.0 up to 3.8.8, plus listed versions v3.8.0v3.8.1v3.8.2v3.8.3v3.8.4v3.8.5v3.8.6v3.8.7	3.8.8
`moodle/moodle` Packagist	3.5 up to 3.5.17, plus listed versions v3.5.0v3.5.0-betav3.5.0-rc1v3.5.1v3.5.10 Show 14 moreShow less v3.5.11v3.5.12v3.5.13v3.5.14v3.5.15v3.5.16v3.5.2v3.5.3v3.5.4v3.5.5v3.5.6v3.5.7v3.5.8v3.5.9	3.5.17
`moodle` Ubuntu:Pro:16.04:LTS	All versions, plus listed versions 2.7.9+dfsg-12.7.10+dfsg-12.7.11+dfsg-12.7.11+dfsg-22.7.12+dfsg-13.0.3+dfsg-0ubuntu13.0.3+dfsg-0ubuntu1+esm1	None known
`moodle` Ubuntu:Pro:18.04:LTS	All versions, plus listed versions 3.0.3+dfsg-0ubuntu13.0.3+dfsg-0ubuntu1+esm1	None known

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-20281 is a medium vulnerability (CVSS 5.3) in Moodle, published March 15, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.36%, the 71st percentile. Fixed in moodle/moodle 3.10.2.

References

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