The "Mark of the Web" was not correctly saved on Windows when files with very long names were downloaded from the Internet.

published 2018-06-11 8 y ago modified 2026-06-17 4 mo ago also EUVD-2017-16740

cvss: 7.5; version 3.0, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.3%; EPSS 1.3% chance of exploitation in 30 days, percentile 71%
public exploits: 0; none known

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.

Patch / fix

fixed in 3 distros 2

Mozilla Firefox 54
Mozilla Firefox ESR 52.2
Mozilla Thunderbird 52.2

suse opensuse

mozilla-nss SLES for SAP 11 SP4, SLES 11 SP4, SLES 11 SP3-TERADATA +3 more 3.29.5-47.3.2
firefox-gcc5 SLES for SAP 11 SP4, SLES 11 SP4, SLES 11 SP3-TERADATA +2 more 5.3.1+r233831-7.1
MozillaFirefox SLES for SAP 11 SP4, SLES 11 SP4, SLES 11 SP3-TERADATA +3 more 52.2.0esr-72.5.2
firefox-libffi-gcc5 SLES for SAP 11 SP4, SLES 11 SP4, SLES 11 SP3-TERADATA +2 more 5.3.1+r233831-7.1
MozillaFirefox-branding-SLED SLES for SAP 11 SP4, SLES 11 SP4, SLES 11 SP3-TERADATA +2 more 52-24.3.44
MozillaFirefox-branding-SLE SLES for SAP 12 SP2, SLES for SAP 12 SP1, SLES for SAP 12 +6 more 52-31.1
MozillaFirefox SLES for SAP 12 SP2, SLES for SAP 12 SP1, SLES for SAP 12 +7 more 52.2.0esr-108.3

suse advisories SUSE-SU-2017:2235-1 SUSE-SU-2017:1669-1

MozillaThunderbird openSUSE Tumbleweed 91.1.1-1.1
MozillaThunderbird Package Hub 12 52.2-36.1

opensuse advisories openSUSE-SU-2024:10601-1 openSUSE-SU-2017:1579-1

Exploit prediction

1.33% chance of exploitation in the next 30 days, higher than 71% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
NVD	3.0	7.5	CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:N/I:P/A:N

Affected products

Mozilla Firefox
Mozilla Firefox ESR
Mozilla Thunderbird

Classification

Weakness

CWE-20 Improper Input Validation

References

mozilla.org /security/advisories/mfsa2017-15/
vendor-advisory
bugzilla.mozilla.org /show_bug.cgi?id=1273265
issue-tracking, vendor-advisory
mozilla.org /security/advisories/mfsa2017-17/
vendor-advisory
mozilla.org /security/advisories/mfsa2017-16/
vendor-advisory
securityfocus.com /bid/99057
vdb-entry, third-party-advisory
securitytracker.com /id/1038689
vdb-entry, third-party-advisory

Sources

CVE List CVE-2017-7765
NVD CVE-2017-7765

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary