CVE-2018-13879

Severity: medium (CVSS 5.4 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2018-07-11 · updated 2026-06-17
Weakness: CWE-79

Description

A reflected XSS issue was discovered in the registration form in Rocket.Chat before 0.66. When one creates an account, the next step will ask for a username. This field will not save HTML control characters but an error will be displayed that shows the attempted username unescaped via packages/rocketchat-ui-login/client/username/username.js in packages/rocketchat-ui-login/client/username/username.html.

Affected products

Rocket.Chat: before 0.66 — fixed in 0.66

How to fix

Upgrade to a fixed version: Rocket.Chat 0.66. Check the vendor advisory for mitigations.

References

https://github.com/RocketChat/Rocket.Chat/issues/10795
https://github.com/RocketChat/Rocket.Chat/issues/10795

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