SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2017-5389

WebExtensions could use the "mozAddonManager" API by modifying the CSP headers on sites with the appropriate permissions and then using host requests to redirect script loads to a malicious site.

MEDIUM 6.1EPSS 0.92%

Does this matter?

Lower severity and a low EPSS score (0.92%). Track it; it rarely justifies an emergency change on its own.

Description

WebExtensions could use the "mozAddonManager" API by modifying the CSP headers on sites with the appropriate permissions and then using host requests to redirect script loads to a malicious site. This allows a malicious extension to then install additional extensions without explicit user permission. This vulnerability affects Firefox < 51.

CVSS 3.0
6.1 MEDIUMCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
EPSS
0.92% probability · 60th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-601
Affected
mozilla/firefox
Source
security@mozilla.org
EPSS trend
0%3%5%27 October 2026: 0.92%27 October 202627 October 2026

EPSS 0.9% since 27 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.