CVE-2019-18860Network attack vector

Cross-site scripting via unvalidated cache manager hostname

Published Mar 20, 2020 · Updated Nov 5, 2025

Cross-site scripting in Squid before 4.9 allows remote attackers to execute script in a cache manager user's browser via a crafted hostname. The cachemgr.cgi tool reflects the host parameter into generated HTML without rejecting HTML or other invalid hostname characters. The script is not used by default, and exploitation requires a user with a susceptible browser to open the attacker-influenced cache manager response.

CVSS severity6.1
Medium
EPSS probability5.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Squid before 4.9 allows remote attackers to execute script in a cache manager user's browser via a crafted hostname. The cachemgr.cgi tool reflects the host parameter into generated HTML without rejecting HTML or other invalid hostname characters. The script is not used by default, and exploitation requires a user with a susceptible browser to open the attacker-influenced cache manager response.

The record

CVE
CVE-2019-18860
Published
Mar 20, 2020
Updated
Nov 5, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-74, CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 20, 2020CVE publishedPublication date reported by the CVE source.
  2. Nov 5, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
6.1CanonicalCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
6.1Red HatCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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