Is CVE-2018-18505 in the CISA KEV catalog?

No. CVE-2018-18505 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2018-18505?

CVE-2018-18505 has a CVSS v3 base score of 10.0 (CRITICAL).

What is the EPSS score for CVE-2018-18505?

CVE-2018-18505 has an EPSS score of 4.54% (90th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2018-18505?

Upgrade firefox on debian unstable to 65.0-1 or later. Fixes are available for 6 affected products.

CVE & CISA-KEV Catalog

CVE-2018-18505

CRITICALEPSS 90th pctl

10.0

CVSS v3

NVD

Description

An earlier fix for an Inter-process Communication (IPC) vulnerability, CVE-2011-3079, added authentication to communication between IPC endpoints and server parents during IPC process creation. This authentication is insufficient for channels created after the IPC process is started, leading to the authentication not being correctly applied to later channels. This could allow for a sandbox escape through IPC channels due to lack of message validation in the listener process. This vulnerability affects Thunderbird < 60.5, Firefox ESR < 60.5, and Firefox < 65.

CWE-287Improper Authentication

How to fix

Remediation Available

firefoxDebian

Fixed in:65.0-1CVE-2018-18505

firefoxUbuntu

Fixed in:65.0+build2-0ubuntu0.14.04.1USN-3874-1

Fixed in:65.0+build2-0ubuntu0.16.04.1USN-3874-1

Fixed in:65.0+build2-0ubuntu0.18.04.1USN-3874-1

thunderbirdUbuntu

Fixed in:1:60.5.1+build2-0ubuntu0.14.04.1USN-3897-1

Fixed in:1:60.5.1+build2-0ubuntu0.16.04.1USN-3897-1

Fixed in:1:60.5.1+build2-0ubuntu0.18.04.1USN-3897-1

DeveloperEditionWindows application

Affected:65.0Fixed in:65.0Mozilla

Affected:60.5.0Fixed in:60.5.0Mozilla

Mozilla Firefox (en-US)Windows application

Affected:60.5.0Fixed in:60.5.0Mozilla

Affected:65.0Fixed in:65.0Mozilla

Mozilla Thunderbird (en-US)Windows application

Affected:60.5.0Fixed in:60.5.0Mozilla

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeChanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Exploit Intelligence

4.54%probability of exploitation in 30 days

90thpercentile

High risk: more likely to be exploited than 90% of all known CVEs.

References

Patch1

bugzilla.mozilla.org

Vendor Advisory3

Third-Party Advisory13

Other references1

lists.opensuse.org

Related Vulnerabilities

Other CWE-287 (Improper Authentication) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-35082	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2023-35078	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2017-7921	Critical	9.8	100%	KEV	-
CVE-2024-7593	Critical	9.8	100%	KEV	-
CVE-2023-46805	High	8.2	100%	KEV + Ransom	-
CVE-2022-40684	Critical	9.8	100%	KEV + Ransom	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-11-25.