CVE-2019-12524Network attack vector

Cache Manager disclosure via encoded-URL ACL bypass

Published Apr 15, 2020 · Updated Aug 4, 2024

Access-control bypass in Squid 3.5.18 through 3.5.28 and 4.0.10 through 4.7 allows remote attackers to read Cache Manager data. The url_regex handler URL-decodes requests before applying the default Cache Manager denial rule, so an encoded manager URL avoids the intended match. No authentication is required; affected 4.x builds require HTTPS support, and successful requests expose confidential proxy and traffic details.

CVSS severity9.8
Critical
EPSS probability4.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Access-control bypass in Squid 3.5.18 through 3.5.28 and 4.0.10 through 4.7 allows remote attackers to read Cache Manager data. The url_regex handler URL-decodes requests before applying the default Cache Manager denial rule, so an encoded manager URL avoids the intended match. No authentication is required; affected 4.x builds require HTTPS support, and successful requests expose confidential proxy and traffic details.

The record

CVE
CVE-2019-12524
Published
Apr 15, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-306, T1210
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 15, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record 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

9.8NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST National Vulnerability DatabaseAV:N/AC:L/Au:N/C:P/I:P/A:P
5.9Amazon LinuxCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/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-306Missing Authentication for Critical Function
T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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