title: Denial of Service in HTTP Header parser in squid proxy
description: 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 request_header_max_size or reply_header_max_size 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
problem types: CWE-400: Uncontrolled Resource Consumption
affected:
{
vendor: squid-cache
product: squid
versions:
version: < 6.5, status: affected
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: LOW
baseScore: 5.3
baseSeverity: MEDIUM
confidentialityImpact: NONE
integrityImpact: NONE
privilegesRequired: NONE
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
version: 3.1
]