CVE-2020-15049
squid: Request smuggling and poisoning attack against the HTTP cache
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · June 26, 2020
Updated · November 21, 2025
Description
A flaw was found in squid. A trusted client is able to perform a request smuggling and poison the HTTP cache contents with crafted HTTP(S) request messages. This attack requires an upstream server to participate in the smuggling and generate the poison response sequence. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
Statement
This issue has been rated as having moderate security impact, (despite of having a higher CVSS scoring) because the attack requires an upstream server to participate in the smuggling attack and generate the poison response sequence, which is really uncommon because most popular software are not vulnerable to participation in this attack. While the vulnerability does exists in squid, it is not easily exploitable and requires participation of other components on the network.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.1 · 8.5CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
CWE-444 · Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')