CVE-2013-4940

YUI Cross-site Scripting (XSS) vulnerability

4.3 MediumFix available

Cross-site scripting (XSS) vulnerability in io.swf in the IO Utility component in Yahoo! YUI 3.10.2, as used in Moodle through 2.1.10, 2.2.x before 2.2.11, 2.3.x before 2.3.8, 2.4.x before 2.4.5, 2.5.x before 2.5.1, and other products, allows remote attackers to inject arbitrary web script or HTML via a crafted string in a URL. NOTE: this vulnerability exists because of a CVE-2013-4939 regression.

Exploit likelihood

1.49%Up 0.4 points since Feb 4, 2022

What each source reports

NVD Score used 4.3

Record: CVE-2013-4940
CVSS 2.0: 4.3 MediumAV:N/AC:M/Au:N/C:N/I:P/A:N
Weakness: CWE-79
Updated: 2026-11-02

CVE List No score

Record: CVE-2013-4940
Updated: 2026-11-02

EUVDEUVD-2013-4784 No score

Record: EUVD-2013-4784
Updated: 2026-11-03

GitHub AdvisoriesGHSA-x5hj-47vv-53p8 5.3

YUI Cross-site Scripting (XSS) vulnerability

Record: GHSA-x5hj-47vv-53p8
CVSS 4.0: 5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
Weakness: CWE-79
Updated: 2026-11-02

OSVGHSA-x5hj-47vv-53p8 5.3

YUI Cross-site Scripting (XSS) vulnerability

Record: GHSA-x5hj-47vv-53p8
CVSS 4.0: 5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
Weakness: CWE-79
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`yui` npm	3.0.0 to 3.10.0	3.10.11
`yui` npm	3.10.12 to 3.10.12	3.10.13
`moodle/moodle` Packagist	before 2.2.11	2.2.11
`moodle/moodle` Packagist	2.3.0 up to 2.3.8	2.3.8
`moodle/moodle` Packagist	2.4.0-rc1 up to 2.4.5	2.4.5
`moodle/moodle` Packagist	2.5.0-beta up to 2.5.1	2.5.1
`yui` npm	3.0.0 up to 3.10.11	3.10.11
`yui` npm	3.10.12 up to 3.10.13	3.10.13
`moodle/moodle` Packagist	2.3.0 up to 2.3.8, plus listed versions v2.3.4v2.3.5v2.3.6v2.3.7	2.3.8
`moodle/moodle` Packagist	2.4.0-rc1 up to 2.4.5, plus listed versions v2.4.0v2.4.0-rc1v2.4.1v2.4.2v2.4.3v2.4.4	2.4.5
`moodle/moodle` Packagist	2.5.0-beta up to 2.5.1, plus listed versions v2.5.0v2.5.0-betav2.5.0-rc1	2.5.1

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-2013-4940 is a medium vulnerability (CVSS 4.3) in Moodle, published July 26, 2013. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.49%, the 74th percentile. Fixed in yui 3.10.11.