The Mozilla Maintenance Service "helper.exe" application creates a temporary directory writable by non-privileged users.

Published 8 y ago 2018-06-11 · modified 4 mo ago 2026-06-17 · JSON

CVSS

5.5

v3.0 · NVD

CISA KEV

not known exploited

EPSS

0.3%

percentile 23%

Public exploits

none known

The Mozilla Maintenance Service "helper.exe" application creates a temporary directory writable by non-privileged users. When this is combined with creation of a junction (a form of symbolic link), protected files in the target directory of the junction can be deleted by the Mozilla Maintenance Service, which has privileged access. Note: This attack requires local system access and only affects Windows. Other operating systems are not affected. This vulnerability affects Firefox ESR < 52.2 and Firefox < 54.

Exploit prediction (EPSS)

0.30% probability of exploitation in the next 30 days, higher than 23% of all scored CVEs.

CVSS scores

Assigned by	Version	Score	Vector
NVD	3.0	5.5	`CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N`
NVD	2.0	3.6	`AV:L/AC:L/Au:N/C:N/I:P/A:P`

Affected products

Mozilla Firefox ESR
Mozilla Firefox

Classification

Weakness

CWE-276 Incorrect Default Permissions

References

securityfocus.com /bid/99057 · vdb-entry, x_refsource_BID, x_transferred
bugzilla.mozilla.org /show_bug.cgi?id=1215648 · x_refsource_CONFIRM, x_transferred
mozilla.org /security/advisories/mfsa2017-15/ · x_refsource_CONFIRM, x_transferred
securitytracker.com /id/1038689 · vdb-entry, x_refsource_SECTRACK, x_transferred
sourceforge.net /p/nsis/bugs/1125/ · x_refsource_MISC, x_transferred
mozilla.org /security/advisories/mfsa2017-16/ · x_refsource_CONFIRM, x_transferred

Sources

CVE List: CVE-2017-7761
NVD: CVE-2017-7761

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