SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2017-7765

Without the Mark of the Web data, the security warning that Windows displays before running executables downloaded from the Internet is not shown.

HIGH 7.5EPSS 1.33%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (1.33%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

The "Mark of the Web" was not correctly saved on Windows when files with very long names were downloaded from the Internet. Without the Mark of the Web data, the security warning that Windows displays before running executables downloaded from the Internet is not shown. Note: This attack only affects Windows operating systems. Other operating systems are unaffected. This vulnerability affects Firefox < 54, Firefox ESR < 52.2, and Thunderbird < 52.2.

CVSS 3.0
7.5 HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
EPSS
1.33% probability · 71th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-20
Affected
mozilla/firefox · mozilla/thunderbird
Source
security@mozilla.org
EPSS trend
0%3%5%27 October 2026: 1.33%27 October 202627 October 2026

EPSS 1.3% 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.

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