SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2021-29944

Lack of escaping allowed HTML injection when a webpage was viewed in Reader View.

MEDIUM 6.1EPSS 0.70%

Does this matter?

Lower severity and a low EPSS score (0.70%). Track it; it rarely justifies an emergency change on its own.

Description

Lack of escaping allowed HTML injection when a webpage was viewed in Reader View. While a Content Security Policy prevents direct code execution, HTML injection is still possible. *Note: This issue only affected Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 88.

CVSS 3.1
6.1 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
EPSS
0.70% probability · 53th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-79
Affected
mozilla/firefox
Source
security@mozilla.org
EPSS trend
0%3%5%26 October 2026: 0.70%26 October 202626 October 2026

EPSS 0.7% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.