Memory safety bugs were reported in Firefox 55.

published 2018-06-11 8 y ago modified 2026-06-17 4 mo ago also EUVD-2017-16786

cvss: 9.8; version 3.0, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 2.3%; EPSS 2.3% chance of exploitation in 30 days, percentile 83%
public exploits: 0; none known

Memory safety bugs were reported in Firefox 55. Some of these bugs showed evidence of memory corruption and we presume that with enough effort that some of these could be exploited to run arbitrary code. This vulnerability affects Firefox < 56.

Patch / fix

fixed in 1 distros 2

Mozilla Firefox 56

ubuntu opensuse

firefox Ubuntu 14.04 LTS 56.0+build6-0ubuntu0.14.04.1
firefox Ubuntu 16.04 LTS 56.0+build6-0ubuntu0.16.04.1
firefox Ubuntu 18.04 LTS 56.0+build6-0ubuntu1

ubuntu advisories UBUNTU-CVE-2017-7811

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

firefox-esr openSUSE Tumbleweed 128.5.1-1.1
MozillaFirefox openSUSE Tumbleweed 92.0-1.2

opensuse advisories openSUSE-SU-2024:14572-1 openSUSE-SU-2024:10600-1

Exploit prediction

2.27% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

bugzilla.mozilla.org https://bugzilla.mozilla.org/buglist.cgi?bug_id=1392105%2C1395919%2C1388113%2C1348955%2C1394522%2C1387659%2C1369560%2C1388045%2C1378658%2C1379414%2C1385112%2C1367497 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
NVD	3.0	9.8	CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD	2.0	10.0	AV:N/AC:L/Au:N/C:C/I:C/A:C

Affected products

Mozilla Firefox

Classification

Weakness

CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

References

bugzilla.mozilla.org /buglist.cgi?bug_id=1392105%2C1395919%2C1388113%2C1348955%2C1394522%2C1387659%2C1369560%2C1388045%2C1378658%2C
exploit, issue-tracking
mozilla.org /security/advisories/mfsa2017-21/
vendor-advisory
securitytracker.com /id/1039465
vdb-entry, third-party-advisory
securityfocus.com /bid/101057
vdb-entry, third-party-advisory

Sources

CVE List CVE-2017-7811
NVD CVE-2017-7811

Fencer Vulns 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