CVE-2021-20280: Moodle/moodle Cross-Site Scripting Vulnerability
MODERATECVE-2021-20280 is a MODERATE (CVSS 5.4) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Moodle/moodle libraries in the Packagist ecosystem. The issue involves cross-site scripting (xss) and server side request forgery (ssrf) in moodle. Remediation is available by upgrading affected packages to version 3.10.2, 3.9.5, 3.8.8, 3.5.17.
CVE-2021-20280 at a Glance
Security Impact
CVSS: 5.4
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N).
How to Fix CVE-2021-20280
To remediate this vulnerability, upgrade all affected Moodle/moodle dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade moodle/moodle to 3.10.2Upgrade moodle/moodle to 3.9.5Upgrade moodle/moodle to 3.8.8Upgrade moodle/moodle to 3.5.17Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for moodle/moodleHow to Check if You Are Affected
To determine whether your application is affected by CVE-2021-20280, inspect your project dependencies for Moodle/moodle:
inspect dependencies for moodle/moodleAnalyze the terminal output to locate any version of Moodle/moodle in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.10.2), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In Moodle/moodle, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2021-20280 Affected Moodle/moodle Versions
4 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
moodle/moodle
|
Packagist |
≥ 3.10
< 3.10.2
|
3.10.2
|
|
moodle/moodle
|
Packagist |
≥ 3.9
< 3.9.5
|
3.9.5
|
|
moodle/moodle
|
Packagist |
≥ 3.8
< 3.8.8
|
3.8.8
|
|
moodle/moodle
|
Packagist |
≥ 3.5
< 3.5.17
|
3.5.17
|
References
Frequently Asked Questions
What is CVE-2021-20280?
Which Moodle/moodle versions are affected?
What version fixes CVE-2021-20280?
Is moodle/moodle affected?
What is the CVSS score of CVE-2021-20280?
What CWE is associated with CVE-2021-20280?
How can I check Packagist dependencies for CVE-2021-20280?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-x2jp-hh65-4xvf",
"modified" : "2021-11-18T15:25:56Z",
"published" : "2021-03-29T20:42:15Z",
"aliases" : [ "CVE-2021-20280" ],
"summary" : "Cross-site scripting (XSS) and Server side request forgery (SSRF) in moodle",
"details" : "Text-based feedback answers required additional sanitizing to prevent stored XSS and blind SSRF risks in moodle before 3.10.2, 3.9.5, 3.8.8, 3.5.17.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Packagist",
"name" : "moodle/moodle"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "3.10"
}, {
"fixed" : "3.10.2"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Packagist",
"name" : "moodle/moodle"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "3.9"
}, {
"fixed" : "3.9.5"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Packagist",
"name" : "moodle/moodle"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "3.8"
}, {
"fixed" : "3.8.8"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Packagist",
"name" : "moodle/moodle"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "3.5"
}, {
"fixed" : "3.5.17"
} ]
} ]
} ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-20280"
}, {
"type" : "WEB",
"url" : "https://github.com/moodle/moodle/commit/a303eb9e9e387f95ea2a80cb1ce6c0b132ec1cc4"
}, {
"type" : "WEB",
"url" : "https://bugzilla.redhat.com/show_bug.cgi?id=1939037"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/moodle/moodle"
}, {
"type" : "WEB",
"url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/AFSNJ7XHVTC52RSRX2GBQFF3VEEAY2MS"
}, {
"type" : "WEB",
"url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/FGOMHMYM3WICJ6D6U22Z6LPJGT5A6MZM"
}, {
"type" : "WEB",
"url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UFH5DDMU5TZ3JT4Q52WMRAHACA5MHIMT"
}, {
"type" : "WEB",
"url" : "https://moodle.org/mod/forum/discuss.php?d=419651"
}, {
"type" : "WEB",
"url" : "http://packetstormsecurity.com/files/164817/Moodle-Cross-Site-Scripting-Server-Side-Request-Forgery.html"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-79" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2021-03-24T23:18:11Z",
"nvd_published_at" : "2021-03-15T22:15:00Z"
}
}