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CVE-2021-26539

MediumCVSS 5.3 / 10
Published Feb 8, 2021·Last modified Mar 14, 2026
Affected Components(29)
apostrophecms/sanitize-html
1.19.1
apostrophecms/sanitize-html
1.10.1
apostrophecms/sanitize-html
1.18.5
1 / 10
Description

Apostrophe Technologies sanitize-html before 2.3.1 does not properly handle internationalized domain name (IDN) which could allow an attacker to bypass hostname whitelist validation set by the "allowedIframeHostnames" option.

Risk Scores
Base Score
5.3

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a low impact on the integrity of the data.

Threat Intelligence
4.9

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

EPSS
1.95%

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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