CVE-2021-36403
CVE-2021-36403 is a medium-severity vulnerability in Moodle with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-912.
Key facts
- Severity: Medium (CVSS 3.x base score 5.3)
- EPSS exploit prediction: 1% (41st percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-912
- Affected product: Moodle
- Published:
- Last modified:
Description
In Moodle, in some circumstances, email notifications of messages could have the link back to the original message hidden by HTML, which may pose a phishing risk.
Frequently asked questions
- What is CVE-2021-36403?
- In Moodle, in some circumstances, email notifications of messages could have the link back to the original message hidden by HTML, which may pose a phishing risk.
- How severe is CVE-2021-36403?
- CVE-2021-36403 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
- Is CVE-2021-36403 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2021-36403?
- CVE-2021-36403 affects Moodle. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2021-36403?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- When was CVE-2021-36403 published?
- CVE-2021-36403 was published on 2023-03-06 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:a:moodle:moodle:*:*:*:*:*:*:*:*
More vulnerabilities in Moodle
- CVE-2006-4935 — Critical (CVSS 10.0): The Database module in Moodle before 1.6.2 does not properly handle uploaded files, which has unspecified impact and…
- CVE-2006-4936 — Critical (CVSS 10.0): Moodle before 1.6.2 does not properly validate the module instance id when creating a course module object, which has…
- CVE-2005-2247 — Critical (CVSS 10.0): Multiple unknown vulnerabilities in Moodle before 1.5.1 have unknown impact and attack vectors.
- CVE-2004-2233 — Critical (CVSS 10.0): Unknown "front page vulnerability with Moodle servers" for Moodle before 1.3.2 has unknown impact and attack vectors.
- CVE-2004-2236 — Critical (CVSS 10.0): Unknown vulnerability in Moodle before 1.3.3 has unknown impact and attack vectors, related to language setting.
- CVE-2004-2237 — Critical (CVSS 10.0): Unknown vulnerability in Moodle before 1.3.4 has unknown impact and attack vectors, related to "strings in Moodle…
Other CWE-912 vulnerabilities
- CVE-2026-3587 — Critical (CVSS 10.0): An unauthenticated remote attacker can exploit a hidden function in the CLI prompt to escape the restricted interface,…
- CVE-2024-39754 — Critical (CVSS 10.0): A static login vulnerability exists in the wctrls functionality of Wavlink AC3000 M33A8.V5030.210505. A specially…
- CVE-2026-1952 — Critical (CVSS 9.8): Delta Electronics AS320T has denial of service via the undocumented subfunction vulnerability.
- CVE-2026-33280 — Critical (CVSS 9.8): Hidden functionality issue exists in BUFFALO Wi-Fi router products, which may allow an attacker to gain access to the…
- CVE-2010-20103 — Critical (CVSS 9.8): A malicious backdoor was embedded in the official ProFTPD 1.3.3c source tarball distributed between November 28 and…
- CVE-2024-45697 — Critical (CVSS 9.8): Certain models of D-Link wireless routers have a hidden functionality where the telnet service is enabled when the WAN…