CVE-2022-0185
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Last Modified:
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Description
A heap-based buffer overflow flaw was found in the way the legacy_parse_param function in the Filesystem Context functionality of the Linux kernel verified the supplied parameters length. An unprivileged (in case of unprivileged user namespaces enabled, otherwise needs namespaced CAP_SYS_ADMIN privilege) local user able to open a filesystem that does not support the Filesystem Context API (and thus fallbacks to legacy handling) could use this flaw to escalate their privileges on the system.
Statement
This issue affects the Linux kernel packages as shipped with Red Hat Enterprise Linux 8.4 GA onwards. Previous Red Hat Enterprise Linux versions are not affected.
Mitigation
On non-containerized deployments of Red Hat Enterprise Linux 8, you can disable user namespaces by setting user.max_user_namespaces to 0:
# echo "user.max_user_namespaces=0" > /etc/sysctl.d/userns.conf
# sysctl -p /etc/sysctl.d/userns.conf
On containerized deployments, such as Red Hat OpenShift Container Platform, do not use this mitigation as the functionality is needed to be enabled.
Additional information
- Bugzilla 2040358: kernel: fs_context: heap overflow in legacy parameter handling
- CWE-191: Integer Underflow (Wrap or Wraparound)
- FAQ: Frequently asked questions about CVE-2022-0185
External references
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 Authority (CNA) source for its products and services (see Red Hat classifications).
| Red Hat | NVD | |
|---|---|---|
CVSS v3 Base Score | 7.8 | 8.4 |
Attack Vector | Local | Local |
Attack Complexity | Low | Low |
Privileges Required | Low | None |
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:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Acknowledgements
Red Hat would like to thank Alec Petridis (alecthechop@gmail.com), Hrvoje Mišetić (misetichrvoje@gmail.com), Isaac Badipe (isaac.badipe@gmail.com), Jamie Hill-Daniel (jamie@hill-daniel.co.uk), Philip Papurt (g@gnk.io), and William Liu (willsroot@protonmail.com) for reporting this issue.
Frequently Asked Questions
Why is Red Hat's CVSS v3 score or Impact different from other vendors?
My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
What can I do if my product is listed as "Will not fix"?
What can I do if my product is listed as "Fix deferred"?
What is a mitigation?
I have a Red Hat product but it is not in the above list, is it affected?
Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?
My product is listed as "Out of Support Scope". What does this mean?
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