Waitress through version 1.3.1 would parse the Transfer-Encoding header and only look for a single string value, if that value was not chunked it would fall through and use the Content-Length header instead. According to the HTTP standard Transfer-Encoding should be a comma separated list, with the inner-most encoding first, followed by any further transfer codings, ending with chunked. Requests sent with: "Transfer-Encoding: gzip, chunked" would incorrectly get ignored, and the request would use a Content-Length header instead to determine the body size of the HTTP message. This could allow for Waitress to treat a single request as multiple requests in the case of HTTP pipelining. This issue is fixed in Waitress 1.4.0.

The remote Redhat Enterprise Linux 8 host has a package installed that is affected by multiple vulnerabilities as referenced in the RHSA-2020:0720 advisory.

    Waitress is a pure Python WSGI server which supports HTTP/1.0 and HTTP/1.1.

    Security Fix(es):

    * HTTP request smuggling through LF vs CRLF handling (CVE-2019-16785)

    * HTTP request smuggling through invalid Transfer-Encoding (CVE-2019-16786)

    * HTTP Request Smuggling through Invalid whitespace characters in headers     (CVE-2019-16789)

    For more details about the security issue(s), including the impact, a CVSS     score, acknowledgments, and other related information, refer to the CVE     page listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Debian 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-3000 advisory.

  - Waitress through version 1.3.1 implemented a MAY part of the RFC7230 which states: Although the line     terminator for the start-line and header fields is the sequence CRLF, a recipient MAY recognize a single     LF as a line terminator and ignore any preceding CR. Unfortunately if a front-end server does not parse     header fields with an LF the same way as it does those with a CRLF it can lead to the front-end and the     back-end server parsing the same HTTP message in two different ways. This can lead to a potential for HTTP     request smuggling/splitting whereby Waitress may see two requests while the front-end server only sees a     single HTTP message. This issue is fixed in Waitress 1.4.0. (CVE-2019-16785)

  - Waitress through version 1.3.1 would parse the Transfer-Encoding header and only look for a single string     value, if that value was not chunked it would fall through and use the Content-Length header instead.
    According to the HTTP standard Transfer-Encoding should be a comma separated list, with the inner-most     encoding first, followed by any further transfer codings, ending with chunked. Requests sent with:
    Transfer-Encoding: gzip, chunked would incorrectly get ignored, and the request would use a Content-     Length header instead to determine the body size of the HTTP message. This could allow for Waitress to     treat a single request as multiple requests in the case of HTTP pipelining. This issue is fixed in     Waitress 1.4.0. (CVE-2019-16786)

  - 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.
    (CVE-2019-16789)

  - Waitress through version 1.3.1 allows request smuggling by sending the Content-Length header twice.
    Waitress would header fold a double Content-Length header and due to being unable to cast the now comma     separated value to an integer would set the Content-Length to 0 internally. If two Content-Length headers     are sent in a single request, Waitress would treat the request as having no body, thereby treating the     body of the request as a new request in HTTP pipelining. This issue is fixed in Waitress 1.4.0.
    (CVE-2019-16792)

  - Waitress is a Web Server Gateway Interface server for Python 2 and 3. When using Waitress versions 2.1.0     and prior behind a proxy that does not properly validate the incoming HTTP request matches the RFC7230     standard, Waitress and the frontend proxy may disagree on where one request starts and where it ends. This     would allow requests to be smuggled via the front-end proxy to waitress and later behavior. There are two     classes of vulnerability that may lead to request smuggling that are addressed by this advisory: The use     of Python's `int()` to parse strings into integers, leading to `+10` to be parsed as `10`, or `0x01` to be     parsed as `1`, where as the standard specifies that the string should contain only digits or hex digits;
    and Waitress does not support chunk extensions, however it was discarding them without validating that     they did not contain illegal characters. This vulnerability has been patched in Waitress 2.1.1. A     workaround is available. When deploying a proxy in front of waitress, turning on any and all functionality     to make sure that the request matches the RFC7230 standard. Certain proxy servers may not have this     functionality though and users are encouraged to upgrade to the latest version of waitress instead.
    (CVE-2022-24761)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

This update for python-waitress to 1.4.3 fixes the following security issues :

  - CVE-2019-16785: HTTP request smuggling through LF vs     CRLF handling (bsc#1161088).

  - CVE-2019-16786: HTTP request smuggling through invalid     Transfer-Encoding (bsc#1161089).

  - CVE-2019-16789: HTTP request smuggling through invalid     whitespace characters (bsc#1160790).

  - CVE-2019-16792: HTTP request smuggling by sending the     Content-Length header twice (bsc#1161670).

This update was imported from the SUSE:SLE-15:Update update project.

According to the versions of the python-waitress package installed, the EulerOS Virtualization for ARM 64 installation on the remote host is affected by the following vulnerabilities :

  - Waitress through version 1.3.1 would parse the     Transfer-Encoding header and only look for a single     string value, if that value was not chunked it would     fall through and use the Content-Length header instead.
    According to the HTTP standard Transfer-Encoding should     be a comma separated list, with the inner-most encoding     first, followed by any further transfer codings, ending     with chunked. Requests sent with: 'Transfer-Encoding:
    gzip, chunked' would incorrectly get ignored, and the     request would use a Content-Length header instead to     determine the body size of the HTTP message. This could     allow for Waitress to treat a single request as     multiple requests in the case of HTTP pipelining. This     issue is fixed in Waitress 1.4.0.(CVE-2019-16786)

  - Waitress through version 1.3.1 implemented a 'MAY' part     of the RFC7230 which states: 'Although the line     terminator for the start-line and header fields is the     sequence CRLF, a recipient MAY recognize a single LF as     a line terminator and ignore any preceding CR.'     Unfortunately if a front-end server does not parse     header fields with an LF the same way as it does those     with a CRLF it can lead to the front-end and the     back-end server parsing the same HTTP message in two     different ways. This can lead to a potential for HTTP     request smuggling/splitting whereby Waitress may see     two requests while the front-end server only sees a     single HTTP message. This issue is fixed in Waitress     1.4.0.(CVE-2019-16785)

  - 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.(CVE-2019-16789)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

According to the versions of the python-waitress package installed, the EulerOS installation on the remote host is affected by the following vulnerabilities :

  - Waitress through version 1.3.1 would parse the     Transfer-Encoding header and only look for a single     string value, if that value was not chunked it would     fall through and use the Content-Length header instead.
    According to the HTTP standard Transfer-Encoding should     be a comma separated list, with the inner-most encoding     first, followed by any further transfer codings, ending     with chunked. Requests sent with: 'Transfer-Encoding:
    gzip, chunked' would incorrectly get ignored, and the     request would use a Content-Length header instead to     determine the body size of the HTTP message. This could     allow for Waitress to treat a single request as     multiple requests in the case of HTTP pipelining. This     issue is fixed in Waitress 1.4.0.(CVE-2019-16786)

  - Waitress through version 1.3.1 implemented a 'MAY' part     of the RFC7230 which states: 'Although the line     terminator for the start-line and header fields is the     sequence CRLF, a recipient MAY recognize a single LF as     a line terminator and ignore any preceding CR.'     Unfortunately if a front-end server does not parse     header fields with an LF the same way as it does those     with a CRLF it can lead to the front-end and the     back-end server parsing the same HTTP message in two     different ways. This can lead to a potential for HTTP     request smuggling/splitting whereby Waitress may see     two requests while the front-end server only sees a     single HTTP message. This issue is fixed in Waitress     1.4.0.(CVE-2019-16785)

  - 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.(CVE-2019-16789)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Update to 1.4.3, fixing CVE-2019-16786 CVE-2019-16785 CVE-2019-16789 and adding various other hardening features.

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website.
Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

ID	Name	Product	Family	Severity
170307	RHEL 8 : python-waitress (RHSA-2020:0720)	Nessus	Red Hat Local Security Checks	high
161188	Debian DLA-3000-1 : waitress - LTS security update	Nessus	Debian Local Security Checks	high
142944	openSUSE Security Update : python-waitress (openSUSE-2020-1911)	Nessus	SuSE Local Security Checks	high
142917	openSUSE Security Update : python-waitress (openSUSE-2020-1922)	Nessus	SuSE Local Security Checks	high
140997	EulerOS Virtualization for ARM 64 3.0.6.0 : python-waitress (EulerOS-SA-2020-2049)	Nessus	Huawei Local Security Checks	high
139982	EulerOS 2.0 SP8 : python-waitress (EulerOS-SA-2020-1879)	Nessus	Huawei Local Security Checks	high
134097	Fedora 31 : python-waitress (2020-65a7744e38)	Nessus	Fedora Local Security Checks	high
134057	Fedora 30 : python-waitress (2020-bdcc8ffc24)	Nessus	Fedora Local Security Checks	high

Detections

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CVE-2019-16786

high

Tenable Plugins

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high

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high