CVE-2021-30465
runc: vulnerable to symlink exchange attack
Severity
ImportantRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · May 19, 2021
Updated · August 11, 2026
Description
The runc package is vulnerable to a symlink exchange attack whereby an attacker can request a seemingly innocuous container configuration that results in the host filesystem being bind-mounted into the container. The highest threat from this vulnerability is to data confidentiality and integrity as well as to system availability.
Statement
OpenShift Container Platform OCP 3.11 be default uses Docker from RHEL-7 extras repository. If using OCP 3.11 upgrade docker on all nodes to a fixed version from the RHEL-7 extras channel. CRI-O could be used instead of Docker on OCP 3.11 and in that case upgrade the runc version from the OCP rpm repository when it becomes available.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
The impact of the vulnerability is reduced if SELinux is in enforcing mode using the container-selinux policy. The container-selinux policy is installed and enabled by default on RHEL 7 and 8, as well as OpenShift Container Platform 3.x and 4.x.
Customers running affected versions of RHEL are strongly recommended to apply RPM updates from the RHEL 8 channel and RHEL 7 Extras channel as soon as errata becomes available.
Customers running affected versions of OpenShift Container Platform are strongly recommended to upgrade as soon as errata becomes available.
Customers of OpenShift Online or OpenShift Dedicated have SELinux enabled in enforcing mode in every host across all clusters. Therefore, It is expected that OSO/OSD both have a reduced impact from this issue, with security patches made available during upcoming maintenance windows.
CVSS / CWE
CVSS 3.1 · 7.5CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE-367 · Time-of-check Time-of-use (TOCTOU) Race Condition