CVE-2020-10711

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Important Important Impact What does this mean?
5.9 CVSS v3 Base Score

Description

A NULL pointer dereference flaw was found in the Linux kernel's SELinux subsystem. This flaw occurs while importing the Commercial IP Security Option (CIPSO) protocol's category bitmap into the SELinux extensible bitmap via the' ebitmap_netlbl_import' routine. While processing the CIPSO restricted bitmap tag in the 'cipso_v4_parsetag_rbm' routine, it sets the security attribute to indicate that the category bitmap is present, even if it has not been allocated. This issue leads to a NULL pointer dereference issue while importing the same category bitmap into SELinux. This flaw allows a remote network user to crash the system kernel, resulting in a denial of service.

Statement

This issue affects the versions of the kernel packages as shipped with the Red Hat Enterprise Linux 6 starting with the Red Hat Enterprise Linux 6.7 GA version kernel-2.6.32-573 . Prior Red Hat Enterprise Linux 6 kernel versions are not affected.

Mitigation

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

This issue can only be resolved by applying updates.

Additional Information

External References

Content from www.cve.org is not included.https://www.cve.org/CVERecord?id=CVE-2020-10711

Content from nvd.nist.gov is not included.https://nvd.nist.gov/vuln/detail/CVE-2020-10711

Affected Packages and Issued Red Hat Security Errata

Products / Services Components State Errata
Red Hat Enterprise Linux 5 kernel Not affected
Red Hat Enterprise Linux 6 kernel Fixed RHSA-2020:2103
Red Hat Enterprise Linux 7 kernel Fixed RHSA-2020:2082
Red Hat Enterprise Linux 7 kernel-rt Fixed RHSA-2020:2085
Red Hat Enterprise Linux 7 kernel-alt Fixed RHSA-2020:2104
Red Hat Enterprise Linux 7.2 Advanced Update Support kernel Fixed RHSA-2020:2285
Red Hat Enterprise Linux 7.3 Advanced Update Support kernel Fixed RHSA-2020:2277
Red Hat Enterprise Linux 7.3 Telco Extended Update Support kernel Fixed RHSA-2020:2277
Red Hat Enterprise Linux 7.3 Update Services for SAP Solutions kernel Fixed RHSA-2020:2277
Red Hat Enterprise Linux 7.4 Advanced Update Support kernel Fixed RHSA-2020:2214
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 5.9 5.9
Attack Vector Network Network
Attack Complexity High High
Privileges Required None None
User Interaction None None
Scope Unchanged Unchanged
Confidentiality Impact None None
Integrity Impact None None
Availability Impact High High

CVSS v3 Vector

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

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

Red Hat CVSS v3 Score Explanation

The above score differs in:

AC:H - Because the said NULL pointer dereference occurs against a specific sequence of network packets only, which is difficult to create. Secondly, it requires that network packet labeling by CIPSO v4 format is enabled, It is not enabled by default IIUC. Also, CIPSO v4 packet labeling is likely to be used in a closed network and/or group of systems within a domain of interpretation (DoI).

From: -> Content from tools.ietf.org is not included.https://tools.ietf.org/id/draft-ietf-cipso-ipsecurity-01.txt

  1. CIPSO Format

Option type: 134 (Class 0, Number 6, Copy on Fragmentation)

This option permits security-related information to be passed between systems within a single Domain of Interpretation (DOI). A DOI is a collection of systems that agree on the meaning of particular values in the security option. An authority that has been assigned a DOI identifier will define a mapping between appropriate CIPSO field values and their human-readable equivalent. This authority will distribute that mapping to hosts within the authority's domain. These mappings may be sensitive, therefore a DOI authority is not required to make these mappings available to anyone other than the systems that are included in the DOI.

Acknowledgements

Red Hat would like to thank Matthew Sheets (gd-ms.com) for reporting this issue.

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.