CVE-2021-40691
Moodle Improper Authentication
A session hijack risk was identified in the Shibboleth authentication plugin.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
A session hijack risk was identified in the Shibboleth authentication plugin.
- Record
CVE-2021-40691- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
CVE List No score
A session hijack risk was identified in the Shibboleth authentication plugin.
- Record
CVE-2021-40691- Updated
- 2026-11-02
EUVDEUVD-2022-6748 No score
A session hijack risk was identified in the Shibboleth authentication plugin.
- Record
EUVD-2022-6748- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-92vh-mr2w-j2cr
Moodle Improper Authentication
A session hijack risk was identified in the Shibboleth authentication plugin.
- Record
GHSA-92vh-mr2w-j2cr- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
OSV
A session hijack risk was identified in the Shibboleth authentication plugin.
- Record
CVE-2021-40691- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
OSVGHSA-92vh-mr2w-j2cr
Moodle Improper Authentication
A session hijack risk was identified in the Shibboleth authentication plugin.
- Record
GHSA-92vh-mr2w-j2cr- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
OSVUBUNTU-CVE-2021-40691
A session hijack risk was identified in the Shibboleth authentication plugin.
- Record
UBUNTU-CVE-2021-40691- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
OSVBIT-moodle-2021-40691 No score
A session hijack risk was identified in the Shibboleth authentication plugin.
- Record
BIT-moodle-2021-40691- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
moodle/moodlePackagist |
3.9 up to 3.9.10 | 3.9.10 |
moodle/moodlePackagist |
3.10 up to 3.10.7 | 3.10.7 |
moodle/moodlePackagist |
3.11 up to 3.11.3 | 3.11.3 |
moodleBitnami |
before 3.9.10, 3.10.0 up to 3.10.7, 3.11.0 up to 3.11.3 | 3.9.103.10.73.11.3 |
moodle/moodlePackagist |
3.9 up to 3.9.10, plus listed versions v3.9.0v3.9.0-betav3.9.0-rc1v3.9.0-rc2v3.9.0-rc3 Show 9 moreShow lessv3.9.1v3.9.2v3.9.3v3.9.4v3.9.5v3.9.6v3.9.7v3.9.8v3.9.9 |
3.9.10 |
moodle/moodlePackagist |
3.10 up to 3.10.7, plus listed versions v3.10.0v3.10.0-betav3.10.0-rc1v3.10.0-rc2v3.10.1 Show 5 moreShow lessv3.10.2v3.10.3v3.10.4v3.10.5v3.10.6 |
3.10.7 |
moodle/moodlePackagist |
3.11 up to 3.11.3, plus listed versions v3.11.0v3.11.0-betav3.11.0-rc1v3.11.0-rc2v3.11.1v3.11.2 |
3.11.3 |
moodleUbuntu: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 |
moodleUbuntu:Pro:18.04:LTS |
All versions, plus listed versions 3.0.3+dfsg-0ubuntu13.0.3+dfsg-0ubuntu1+esm1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-40691 is a medium vulnerability (CVSS 4.3) in Moodle, published January 21, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.71%, the 53rd percentile. Fixed in moodle/moodle 3.9.10.