CVE-2018-18497 - firefox: WebExtensions can load arbitrary URLs through pipe separators

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MEDIUM

firefox: WebExtensions can load arbitrary URLs through pipe separators

Published Feb 28, 2019

6.5

MEDIUM

CVSS 3.0

EPSS 1.65%

Description

Limitations on the URIs allowed to WebExtensions by the browser.windows.create API can be bypassed when a pipe in the URL field is used within the extension to load multiple pages as a single argument. This could allow a malicious WebExtension to open privileged about: or file: locations. This vulnerability affects Firefox < 64.

Affected products

Vendor Mozilla Product Firefox Default
n/a
- Version
  unspecified
  Status
  affected
  Constraints
  <64

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor

Product

Default status

Versions

Mozilla

Firefox

n/a

Version	Status	Constraints
unspecified	affected	<64

Red Hat Enterprise Linux 6

firefox

Will not fix
Red Hat Enterprise Linux 7

firefox

Will not fix
Red Hat Enterprise Linux 8

firefox

Will not fix

Product	Package	State	Advisory
Red Hat Enterprise Linux 6	firefox	Will not fix	n/a
Red Hat Enterprise Linux 7	firefox	Will not fix	n/a
Red Hat Enterprise Linux 8	firefox	Will not fix	n/a

Remediation

No remediation recorded yet.

Metrics

1.65% 0.01649

Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 4, 2026.

EPSS probability 0.01649

Score over time

2021-2026

EPSS v1
EPSS v5
EPSS v2
EPSS v3
EPSS v4

Percentile over time

EPSS v1
EPSS v5
EPSS v2
EPSS v3
EPSS v4

Table of values (13 key points)

Flat stretches are collapsed. Showing up to 120 newest points.

Date	Score	Percentile	Model
Oct 4, 2026	1.65% (0.01649)	75.68th	v5 (v2026.06.15)
Jun 15, 2026	1.42% (0.01422)	69.29th	v5 (v2026.06.15)
Mar 30, 2025	0.99% (0.00986)	74.80th	v4 (v2025.03.14)
Mar 29, 2025	2.93% (0.02927)	77.34th	v4 (v2025.03.14)
Jul 20, 2024	0.26% (0.00256)	65.81th	v3 (v2023.03.01)
Feb 22, 2024	0.26% (0.00256)	64.55th	v3 (v2023.03.01)
Feb 8, 2024	0.29% (0.00286)	67.93th	v3 (v2023.03.01)
Sep 3, 2023	0.29% (0.00286)	64.78th	v3 (v2023.03.01)
Mar 7, 2023	0.32% (0.00318)	65.73th	v3 (v2023.03.01)
Mar 6, 2023	1.02% (0.01018)	40.69th	v2 (v2022.01.01)
Feb 4, 2022	1.02% (0.01018)	19.50th	v2 (v2022.01.01)
Feb 3, 2022	1.10% (0.01105)	29.18th	v5 (v2026.06.15)
Apr 14, 2021	1.10% (0.01105)	0.00th	v1

Weaknesses (1)

CWE-939

References (8)

http://www.securityfocus.com/bid/106167
vdb-entryx_refsource_BIDThird Party AdvisoryVDB Entry
https://access.redhat.com/security/cve/CVE-2018-18497
Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1488180
x_refsource_CONFIRMIssue TrackingPermissions RequiredVendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1696112
Issue Tracking
https://nvd.nist.gov/vuln/detail/CVE-2018-18497
https://usn.ubuntu.com/3844-1/
vendor-advisoryx_refsource_UBUNTUThird Party Advisory
https://www.cve.org/CVERecord?id=CVE-2018-18497
https://www.mozilla.org/security/advisories/mfsa2018-29/
x_refsource_CONFIRMVendor Advisory

Link	Providers	Tags
http://www.securityfocus.com/bid/106167		vdb-entryx_refsource_BIDThird Party AdvisoryVDB Entry
https://access.redhat.com/security/cve/CVE-2018-18497		Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1488180		x_refsource_CONFIRMIssue TrackingPermissions RequiredVendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1696112		Issue Tracking
https://nvd.nist.gov/vuln/detail/CVE-2018-18497
https://usn.ubuntu.com/3844-1/		vendor-advisoryx_refsource_UBUNTUThird Party Advisory
https://www.cve.org/CVERecord?id=CVE-2018-18497
https://www.mozilla.org/security/advisories/mfsa2018-29/		x_refsource_CONFIRMVendor Advisory