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GHSA-c5f8-35qr-q4fm

MediumCVSS 6.1 / 10
Published Mar 26, 2021·Last modified Mar 13, 2026
Affected Components(0)

No affected components available

Description

Impact

The notification emails sent for notifications for missed messages or for an expiring account are subject to HTML injection. In the case of the notification for missed messages, this could allow an attacker to insert forged content into the email.

The account expiry feature is not enabled by default and the HTML injection is not controllable by an attacker.

Patches

This issue is fixed in #9200.

Workarounds

For the missed messages notifications:

The notif.html, notif_mail.html, and room.html templates can be overridden with custom templates that manually escapes the variables using JInja2's escape filter. See the email.template_dir setting.

For the account expiry notifications:

  1. Account expiry can be disabled via the account_validity.enabled setting.

  2. The notice_expiry.html template can be overridden with a custom template that manually escapes the variables using JInja2's escape filter. See the email.template_dir setting.

Risk Scores
Base Score
6.1

The vulnerability can be exploited over the network without needing physical access. It is difficult for an attacker to exploit this vulnerability and may require special conditions. An attacker does not need any special privileges or access rights. The attacker needs the user to perform some action, like clicking a link. The vulnerability can affect other systems as well, not just the initial system. There is a high impact on the integrity of the data.

Threat Intelligence
5.6

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
1.39%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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