denial of service in HTTP header parser
CVE: CVE-2024-25617
Component: squid
CWE: CWE-400
Severity: Important
CVSS v3: 8.5/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Release date: 2024-02-14T00:00:00+00:00

A flaw was found in Squid. This issue may allow a remote client or remote server to trigger a denial of service when sending oversized headers in HTTP messages.

Statement: This issue can be exploitable when the Squid request_header_max_size and reply_header_max_size configuration options have a big value, specifically, values greater than 64KB. In Squid versions prior to 6.5, the default value of these options are unsafe.
The Squid package as shipped in Red Hat Enterprise Linux 7, 8 and 9 has an unsafe default configuration and is vulnerable to this issue.

Remediation:
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

After installing this update, the squid service will be restarted automatically.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

After installing this update, the squid service will be restarted automatically.
For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

After installing this update, the squid service will be restarted automatically.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

After installing this update, the squid service will be restarted automatically.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

After installing this update, the squid service will be restarted automatically.
For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

After installing this update, the squid service will be restarted automatically.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

After installing this update, the squid service will be restarted automatically.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

After installing this update, the squid service will be restarted automatically.
Before applying this update, make sure all previously released errata relevant to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258
To mitigate this flaw in Squid versions prior to 6.5, set the request_header_max_size and reply_header_max_size configuration options to 21KB. The following lines should be added to the Squid configuration file:

~~~
request_header_max_size 21 KB
reply_header_max_size 21 KB
~~~

In Squid versions 6.5 and newer, the default values of these options are considered safe and the above configuration can be removed. Also, Squid will emit a warning in the logs if the configured values are unsafe.