CVE-2020-15049: An issue was discovered in http/ContentLengthInterpreter.cc in Squid before 4.12 and 5.x before 5.0.3. A Request Smuggling and Poisoning attack can su...

Description

An issue was discovered in http/ContentLengthInterpreter.cc in Squid before 4.12 and 5.x before 5.0.3. A Request Smuggling and Poisoning attack can succeed against the HTTP cache. The client sends an HTTP request with a Content-Length header containing "+\ "-" or an uncommon shell whitespace character prefix to the length field-value.

Metrics

CVSS 3.1

8.8/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

5.71%

92.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-444

Affected Software

Vendor	Product	Versions
Squid-Cache	Squid	>= 2.0, <= 2.6
Squid-Cache	Squid	>= 3.1, <= 3.5.28
Squid-Cache	Squid	>= 4.0, < 4.12
Squid-Cache	Squid	>= 5.0, < 5.0.3
Squid-Cache	Squid	2.7
Fedoraproject	Fedora	31

References

Timeline

Published: Jun 30, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-15049?

An issue was discovered in http/ContentLengthInterpreter.cc in Squid before 4.12 and 5.x before 5.0.3. A Request Smuggling and Poisoning attack can succeed against the HTTP cache. The client sends an HTTP request with a Content-Length header containing "+\ "-" or an uncommon shell whitespace character prefix to the length field-value.

How severe is CVE-2020-15049?

CVE-2020-15049 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 5.71% probability of exploitation in the next 30 days.

How do I fix CVE-2020-15049?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.