What’s Vulnerable › Vulnerabilities

CVE-2019-18860

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 5.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-03-20 · updated 2026-06-17
• Weakness: CWE-74

Description

Squid before 4.9, when certain web browsers are used, mishandles HTML in the host (aka hostname) parameter to cachemgr.cgi.

Affected products

• Canonical Ubuntu Linux: 16.04, 18.04, 19.10, 20.04
• Debian Linux: 9.0, 10.0
• openSUSE Leap: 15.1
• Squid: before 4.9 — fixed in 4.9

How to fix

Upgrade to a fixed version: Squid 4.9. Check the vendor advisory for mitigations.

References

• http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00018.html
• https://github.com/squid-cache/squid/pull/504
• https://github.com/squid-cache/squid/pull/505
• https://lists.debian.org/debian-lts-announce/2020/07/msg00009.html
• https://usn.ubuntu.com/4356-1/
• https://www.debian.org/security/2020/dsa-4732
• http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00018.html
• http://www.openwall.com/lists/oss-security/2025/11/04/7
• http://www.openwall.com/lists/oss-security/2025/11/05/1
• http://www.openwall.com/lists/oss-security/2025/11/05/7
• https://github.com/squid-cache/squid/pull/504
• https://github.com/squid-cache/squid/pull/505

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