CVE-2020-11100

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Last Modified: UTC

Critical Critical Impact What does this mean?
8.8 CVSS v3 Base Score

Description

A flaw was found in the way HAProxy processed certain HTTP/2 request packets. This flaw allows an attacker to send crafted HTTP/2 request packets, which cause memory corruption, leading to a crash or potential remote arbitrary code execution with the permissions of the user running HAProxy.

Statement

HAProxy packages shipped with Red Hat Enterprise Linux 6 and 7 do not contain support for HTTP/2; therefore, they are not affected by this flaw.

OpenShift Container Platform versions through 4.3 contain the vulnerable code; exploitation requires setting ROUTER_USE_HTTP2 in the OpenShift Ingress Operator, which is not currently possible. The impact of this vulnerability is therefore reduced in OCP 4.x, prior to version 4.4, to low.

OpenShift Container Platform 3.11 added a configuration option to ose-haproxy-router that made enabling HTTP/2 support easy. However, it is not enabled by default on that version.

Mitigation

This issue can be mitigated by not enabling support for HTTP/2 protocol. Upstream suggests that HTTP/2 can be enabled per front-end server by using the following documentation: This content is not included.https://www.haproxy.com/documentation/hapee/1-8r1/traffic-management/enable-http2-protocol/.

You can check if http2 is enabled by searching your haproxy configuration files for a line containing 'h2'.

To mitigate this vulnerability in OpenShift Container Platform 3.11, keep HTTP/2 disabled as it is by default. You can verify if HTTP/2 support is enabled or not by following the instructions in following article: This content is not included.https://access.redhat.com/security/vulnerabilities/haproxy

On Red Hat Enterprise Linux 8, haproxy is confined by SELinux, which should mitigate remote arbitrary code execution.

Additional Information

External References

Content from www.cve.org is not included.https://www.cve.org/CVERecord?id=CVE-2020-11100

Content from nvd.nist.gov is not included.https://nvd.nist.gov/vuln/detail/CVE-2020-11100

Content from bugs.chromium.org is not included.https://bugs.chromium.org/p/project-zero/issues/detail?id=2023

Content from www.haproxy.com is not included.https://www.haproxy.com/blog/haproxy-1-8-http-2-hpack-decoder-vulnerability-fixed/

Content from www.mail-archive.com is not included.https://www.mail-archive.com/haproxy@formilux.org/msg36876.html

Affected Packages and Issued Red Hat Security Errata

Products / Services Components State Errata
Red Hat Enterprise Linux 6 haproxy Not affected
Red Hat Enterprise Linux 7 haproxy Not affected
Red Hat Enterprise Linux 8 haproxy Fixed RHSA-2020:1288
Red Hat Enterprise Linux 8.0 Update Services for SAP Solutions haproxy Fixed RHSA-2020:1289
Red Hat OpenShift Container Platform 3.11 haproxy Fixed RHSA-2020:1287
Red Hat OpenShift Container Platform 4.4 haproxy Fixed RHSA-2020:1936
Red Hat Software Collections for Red Hat Enterprise Linux 7 rh-haproxy18-haproxy Fixed RHSA-2020:1290
Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS rh-haproxy18-haproxy Fixed RHSA-2020:1290
Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS rh-haproxy18-haproxy Fixed RHSA-2020:1290
Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS rh-haproxy18-haproxy Fixed RHSA-2020:1290
Unless explicitly stated as not affected, all previous versions of packages in any minor update stream of a product listed here should be assumed vulnerable, although may not have been subject to full analysis.

Common Vulnerability Scoring System (CVSS) Score Details

Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authorities (CNA) source for its products and services (see Red Hat classifications ).

CVSS v3 Score Breakdown Red Hat NVD
CVSS v3 Base Score 8.8 8.8
Attack Vector Network Network
Attack Complexity Low Low
Privileges Required Low Low
User Interaction None None
Scope Unchanged Unchanged
Confidentiality Impact High High
Integrity Impact High High
Availability Impact High High

CVSS v3 Vector

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

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

Acknowledgements

Red Hat would like to thank the HAProxy project for reporting this issue. Upstream acknowledges Felix Wilhelm (Google Project Zero) as the original reporter.

Frequently Asked Questions

Why is Red Hat's CVSS v3 score or Impact different from other vendors?

 For open source software shipped by multiple vendors, the CVSS base scores may vary for each vendor's version depending on the version they ship, how they ship it, the platform, and even how the software is compiled. This makes scoring of vulnerabilities difficult for third-party vulnerability databases such as NVD that only provide a single CVSS base score for each vulnerability. Red Hat scores reflect how a vulnerability affects our products specifically.

For more information, see https://access.redhat.com/solutions/762393.

My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
  • "Under investigation" doesn't necessarily mean that the product is affected by this vulnerability. It only means that our Analysis Team is still working on determining whether the product is affected and how it is affected.
  • "Affected" means that our Analysis Team has determined that this product is affected by this vulnerability and might release a fix to address this in the near future.

What can I do if my product is listed as "Will not fix"?

 A "will not fix" status means that a fix for an affected product version is not planned or not possible due to complexity, which may create additional risk.

Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
  • Upgrade to a supported product version that includes a fix for this vulnerability (recommended).
  • Apply a mitigation (if one exists).
  • Open a This content is not included.support case to request a prioritization of releasing a fix for this vulnerability.

What can I do if my product is listed as "Fix deferred"?

 A deferred status means that a fix for an affected product version is not guaranteed due to higher-priority development work.

Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
  • Apply a mitigation (if one exists).
  • Open a This content is not included.support case to request a prioritization of releasing a fix for this vulnerability.
  • Red Hat Engineering focuses on addressing high-priority issues based on their complexity or limited lifecycle support. Therefore, lower-priority issues will not receive immediate fixes.

What is a mitigation?

 A mitigation is an action that can be taken to reduce the impact of a security vulnerability, without deploying any fixes.

I have a Red Hat product but it is not in the above list, is it affected?

 The listed products were found to include one or more of the components that this vulnerability affects. These products underwent a thorough evaluation to determine their affectedness by this vulnerability. Note that layered products (such as container-based offerings) that consume affected components from any of the products listed in this table may be affected and are not represented.

Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?

 In order to maintain code stability and compatibility, Red Hat usually does not rebase packages to entirely new versions. Instead, we backport fixes and new features to an older version of the package we distribute. This can result in some security scanners that only consider the package version to report the package as vulnerable. To avoid this, we suggest that you use an approved vulnerability scanner from our This content is not included.Red Hat Vulnerability Scanner Certification program.