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CVE-2019-16789

HIGHCVSS 8.2/10EPSS 2.59%

Last modified

CVE-2019-16789 is a high-severity vulnerability rated 8.2/10 on the CVSS scale. In Waitress through version 1.4.0, if a proxy server is used in front of waitress, an invalid request may be sent by an attacker that bypasses the front-end and is parsed differently by waitress leading to a potential for HTTP request smuggling. Specially crafted requests containing special whitespace characters in the Transfer-Encoding header would get parsed by Waitress as being a chunked request, but a front-end server would use the Content-Length instead as the Transfer-Encoding header is considered invalid due to containing invalid characters. EPSS estimates a 2.59% chance of exploitation in the next 30 days.

Description

In Waitress through version 1.4.0, if a proxy server is used in front of waitress, an invalid request may be sent by an attacker that bypasses the front-end and is parsed differently by waitress leading to a potential for HTTP request smuggling. Specially crafted requests containing special whitespace characters in the Transfer-Encoding header would get parsed by Waitress as being a chunked request, but a front-end server would use the Content-Length instead as the Transfer-Encoding header is considered invalid due to containing invalid characters. If a front-end server does HTTP pipelining to a backend Waitress server this could lead to HTTP request splitting which may lead to potential cache poisoning or unexpected information disclosure. This issue is fixed in Waitress 1.4.1 through more strict HTTP field validation.

Metrics

CVSS 3.1
8.2/10

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

EPSS Probability
2.59%

83.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
AgendalessWaitress<= 1.4.0
OracleCommunications Cloud Native Core Network Function Cloud Native Environment1.10.0
DebianDebian Linux9.0
FedoraprojectFedora30
FedoraprojectFedora31
RedhatOpenstack15

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2019-16789?
In Waitress through version 1.4.0, if a proxy server is used in front of waitress, an invalid request may be sent by an attacker that bypasses the front-end and is parsed differently by waitress leading to a potential for HTTP request smuggling. Specially crafted requests containing special whitespace characters in the Transfer-Encoding header would get parsed by Waitress as being a chunked request, but a front-end server would use the Content-Length instead as the Transfer-Encoding header is considered invalid due to containing invalid characters. If a front-end server does HTTP pipelining to a backend Waitress server this could lead to HTTP request splitting which may lead to potential cache poisoning or unexpected information disclosure. This issue is fixed in Waitress 1.4.1 through more strict HTTP field validation.
How severe is CVE-2019-16789?
CVE-2019-16789 has a CVSS score of 8.2/10 (HIGH severity). The EPSS model estimates a 2.59% probability of exploitation in the next 30 days.
How do I fix CVE-2019-16789?
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.

Are you affected by CVE-2019-16789?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST