__________________________________________________________________
Squid Proxy Cache Security Update Advisory SQUID-2025:2
__________________________________________________________________
Advisory ID: | SQUID-2025:2
Date: | Oct 15, 2025
Summary: | Information Disclosure in Error handling.
Affected versions: | Squid 3.x -> 3.5.28
| Squid 4.x -> 4.17
| Squid 5.x -> 5.9
| Squid 6.x -> 6.14
| Squid 7.x -> 7.1
Fixed in version: | Squid 7.2
__________________________________________________________________
Problem Description:
Due to a failure to redact HTTP Authentication credentials
Squid is vulnerable to an Information Disclosure attack.
__________________________________________________________________
Severity:
This problem allows a script to bypass Browser security
protections and learn the credentials a trusted client uses to
authenticate.
This problem 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.
__________________________________________________________________
Updated Packages:
This bug is fixed by Squid version 7.2.
In addition, patches addressing this problem for the stable
releases can be found in our patch archives:
Squid 7:
<https://github.com/squid-cache/squid/commit/0951a0681011dfca3d78c84fd7f1e19c78a4443f>
If you are using a prepackaged version of Squid then please
refer to the package vendor for availability information on
updated packages.
__________________________________________________________________
Determining if your version is vulnerable:
The following test can be used to determine if your Squid has
a vulnerable configuration:
squid -k parse 2>&1 | grep "email_err_data"
All Squid with `email_err_data off` are not vulnerable.
All Squid up to and including 7.1 with `email_err_data on`
are vulnerable.
All Squid up to and including 7.1 without `email_err_data`
are vulnerable.
__________________________________________________________________
Workaround:
Disable debug information in administrator mailto links
generated by Squid. By configuring squid.conf with:
email_err_data off
__________________________________________________________________
Contact details for the Squid project:
For installation / upgrade support on binary packaged versions
of Squid: Your first point of contact should be your binary
package vendor.
If you install and build Squid from the original Squid sources
then the <[email protected]> mailing list is
your primary support point. For subscription details see
<http://www.squid-cache.org/Support/mailing-lists.html>.
For reporting of non-security bugs in the latest STABLE release
the squid bugzilla database should be used
<https://bugs.squid-cache.org/>.
For reporting of security sensitive bugs send an email to the
<[email protected]> mailing list. It's a closed
list (though anyone can post) and security related bug reports
are treated in confidence until the impact has been established.
__________________________________________________________________
Credits:
This vulnerability was discovered by Leonardo Giovannini of
Doyensec.
Fixed by Amos Jeffries of Treehouse Networks Ltd.
__________________________________________________________________
Revision history:
2025-09-12 08:52:20 UTC Initial Report
2025-10-11 07:42:00 UTC Patch Released
2025-10-13 14:35:00 UTC CVE Assignment
__________________________________________________________________
END
_______________________________________________
squid-announce mailing list
[email protected]
https://lists.squid-cache.org/listinfo/squid-announce
