CVEvulnerability

CVE-2020-15811

6.5 MEDIUM Published 2020-09-02 Modified 2026-06-17 Official page ↗
Status
Modified
Published
2020-09-02
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
6.5 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
CVSS 2.0 ([email protected])
4.0 MEDIUM — AV:N/AC:L/Au:S/C:N/I:P/A:N
Weaknesses
CWE-697

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 configurations

• squid-cache squid (< 4.13) • squid-cache squid (>= 5.0 < 5.0.4) • canonical ubuntu linux 16.04 • canonical ubuntu linux 18.04 • canonical ubuntu linux 20.04 • debian debian linux 9.0 • debian debian linux 10.0 • fedoraproject fedora 31 • fedoraproject fedora 32 • fedoraproject fedora 33 • opensuse leap 15.1 • opensuse leap 15.2

Related

Weakness · CWE (1)

  • CWE-697 Incorrect Comparison weakness

Referenced by CWE · observed example (2)

  • CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers weakness
  • CWE-697 Incorrect Comparison weakness

References