CVE-2024-25617: Denial of Service in HTTP Header parser in squid proxy
Last updated 13 January 2025
Other sources
Squid is an open source caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Due to a Collapse of Data into Unsafe Value bug ,Squid may be vulnerable to a Denial of Service attack against HTTP header parsing. This problem allows a remote client or a remote server to perform Denial of Service when sending oversized headers in HTTP messages. In versions of Squid prior to 6.5 this can be achieved if the requestheadermaxsize or replyheadermaxsize settings are unchanged from the default. In Squid version 6.5 and later, the default setting of these parameters is safe. Squid will emit a critical warning in cache.log if the administrator is setting these parameters to unsafe values. Squid will not at this time prevent these settings from being changed to unsafe values. Users are advised to upgrade to version 6.5. There are no known workarounds for this vulnerability. This issue is also tracked as SQUID-2024:2
— Launchpad
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
redhat/squidto a version that resolves this vulnerability.Fixed in 6.5 - Upgrade
Upgrade
debian/squidto a version that resolves this vulnerability.Fixed in 4.13-10+deb11u3Fixed in 5.7-2+deb12u2Fixed in 6.13-1 - Upgrade
Upgrade
squid-cache/squidto a version that resolves this vulnerability.Fixed in 6.5 - Configuration
For Squid versions prior to 6.5, ensure request_header_max_size and reply_header_max_size are left unchanged from their default safe values; do not set them to unsafe values (Squid logs a critical warning in cache.log when set to unsafe values).
Squid proxy request_header_max_size or reply_header_max_size = unchanged from the default (safe)
Event History
Frequently Asked Questions
What is the severity of CVE-2024-25617?
CVE-2024-25617 is considered a high severity vulnerability due to the potential for Denial of Service attacks.
How do I fix CVE-2024-25617?
To fix CVE-2024-25617, upgrade Squid to version 6.5 or any patched version specific to Debian as detailed in the security advisories.
Which versions of Squid are affected by CVE-2024-25617?
CVE-2024-25617 affects Squid versions prior to 6.5 and specific older versions of Squid on Debian and Red Hat.
Is there a workaround for CVE-2024-25617?
Currently, there is no official workaround for CVE-2024-25617, and it's advised to upgrade to a secured version.
What kind of attack can CVE-2024-25617 lead to?
CVE-2024-25617 can lead to Denial of Service attacks that disrupt HTTP header parsing in Squid.