Vulnerability in Squid-Cache Squid
CVE-2020-15810
An issue was discovered in Squid before 4.13 and 5.x before 5.0.4. Due to incorrect data validation, HTTP Request Smuggling 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 proxy cache and any downstream caches with content from an arbitrary source. When configured for relaxed header parsing (the default), Squid relays headers containing whitespace characters to upstream servers. When this occurs as a prefix to a Content-Length header, the frame length specified will be ignored by Squid (allowing for a conflicting length to be used from another Content-Length header) but relayed upstream.
Vulnerability class: HTTP Request Smuggling
EPSS: 0.025 (83.2th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N.
Affected products
- Squid-cache Squid
- Canonical Ubuntu_linux — versions 16.04, 18.04, 20.04
- Debian Debian_linux — versions 9.0, 10.0
- Fedoraproject Fedora — versions 31, 32, 33
- Opensuse Leap — versions 15.1, 15.2
- N/a — versions n/a
Weakness classification (CWE)
Public proof-of-concept exploits
References
- cve@mitre.org (Third Party Advisory, x_refsource_MISC, Mitigation)
- cve@mitre.org (vendor-advisory, Third Party Advisory, x_refsource_DEBIAN)
- cve@mitre.org (x_refsource_UBUNTU, vendor-advisory, Third Party Advisory)
- cve@mitre.org (x_refsource_FEDORA, vendor-advisory)
- cve@mitre.org (x_refsource_FEDORA, vendor-advisory)
- cve@mitre.org (vendor-advisory, Mailing List, Third Party Advisory, x_refsource_SUSE)
- cve@mitre.org (vendor-advisory, Mailing List, Third Party Advisory, x_refsource_SUSE)
- cve@mitre.org (x_refsource_FEDORA, vendor-advisory)
- cve@mitre.org (x_refsource_UBUNTU, vendor-advisory, Third Party Advisory)
- cve@mitre.org (mailing-list, x_refsource_MLIST, Mailing List, Third Party Advisory)
Frequently asked questions
- What is CVE-2020-15810?
- CVE-2020-15810 is a medium-severity vulnerability in Squid-Cache Squid, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 6.5/10. Published 2020-09-02.
- How severe is CVE-2020-15810?
- Medium severity. CVSS v3 base score is 6.5 out of 10.
- Is CVE-2020-15810 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.