How severe is CVE-2015-5331?

CVE-2015-5331 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2015-5331 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2015-5331?

CVE-2015-5331 primarily affects Moodle. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2015-5331?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2015-5331 published?

CVE-2015-5331 was published on 2016-02-22 and last updated on 2026-06-17.

CVE-2015-5331

CVE-2015-5331 is a medium-severity vulnerability in Moodle with a CVSS 3.x base score of 4.3. 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-254.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
CVSS v2: 4.0
EPSS exploit prediction: 1% (67th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-254
Affected product: Moodle
Published: 2016-02-22
Last modified: 2026-06-17

Description

Moodle 2.9.x before 2.9.3 does not properly check the contact list before authorizing message transmission, which allows remote authenticated users to bypass intended access restrictions and conduct spam attacks via the messaging API.

Frequently asked questions

What is CVE-2015-5331?: Moodle 2.9.x before 2.9.3 does not properly check the contact list before authorizing message transmission, which allows remote authenticated users to bypass intended access restrictions and conduct spam attacks via the messaging API.
How severe is CVE-2015-5331?: CVE-2015-5331 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2015-5331 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2015-5331?: CVE-2015-5331 primarily affects Moodle. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2015-5331?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2015-5331 published?: CVE-2015-5331 was published on 2016-02-22 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:moodle:moodle:2.9.0:*:*:*:*:*:*:*
cpe:2.3:a:moodle:moodle:2.9.1:*:*:*:*:*:*:*
cpe:2.3:a:moodle:moodle:2.9.2:*:*:*:*:*:*:*

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