CVE-2020-15811

MEDIUM
6.5
CVSS Score
Published: September 2, 2020 at 04:35 PM UTC
Updated: June 17, 2026 at 02:57 AM UTC
5 products affected across 5 vendorsDebian LinuxFedoraUbuntu Linux

Using N/A by N/A?

Get instant alerts when new vulnerabilities affect N/A - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
MEDIUM6.5
Exploit prediction
EPSS 4%

Description

An issue was discovered in Squid before 4.13 and 5.x before 5.0.4. Due to incorrect data validation, HTTP Request Splitting attacks may succeed against HTTP and HTTPS traffic. This leads to cache poisoning. This allows any client, including browser scripts, to bypass local security and poison the browser cache and any downstream caches with content from an arbitrary source. Squid uses a string search instead of parsing the Transfer-Encoding header to find chunked encoding. This allows an attacker to hide a second request inside Transfer-Encoding: it is interpreted by Squid as chunked and split out into a second request delivered upstream. Squid will then deliver two distinct responses to the client, corrupting any downstream caches.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 4.135.0 ≤ v < 5.0.4
Affected range stops below 4.13, so it looks safe — our inference, not a vendor statement
Affected range stops below 5.0.4, so it looks safe — our inference, not a vendor statement

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-697

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card