Squid is a caching proxy for the Web. In Squid versions prior to 7.2, a failure to redact HTTP authentication credentials in error handling allows information disclosure. The vulnerability allows a script to bypass browser security protections and learn the credentials a trusted client uses to authenticate.
This potentially allows a remote client to identify security tokens or credentials used internally by a web application using Squid for backend load balancing. These attacks do not require Squid to be configured with HTTP authentication. The vulnerability is fixed in version 7.2.
As a workaround, disable debug information in administrator mailto links generated by Squid by configuring squid.conf with email_err_data off.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
None
No data modification
Availability
None
No disruption
CVSS Vector v3.1
Weakness Type (CWE)
Vulnerable Products 1
| Configuration | From (including) | Up to (excluding) |
|---|---|---|
|
Squid-Cache Squid
cpe:2.3:a:squid-cache:squid:*:*:*:*:*:*:*:*
|
— |
7.2
|
References 3
https://github.com/squid-cache/squid/commit/0951a0681011dfca3d78c84fd7f1e19c78a…
security-advisories@github.com
https://github.com/squid-cache/squid/security/advisories/GHSA-c8cc-phh7-xmxr
security-advisories@github.com
http://www.openwall.com/lists/oss-security/2025/11/05/6
af854a3a-2127-422b-91ae-364da2661108