CVE-2019-18837

Severity: high (CVSS 8.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2019-11-13 · updated 2026-06-17
Weakness: CWE-59

Description

An issue was discovered in crun before 0.10.5. With a crafted image, it doesn't correctly check whether a target is a symlink, resulting in access to files outside of the container. This occurs in libcrun/linux.c and libcrun/chroot_realpath.c.

Affected products

containers crun: before 0.10.5 — fixed in 0.10.5
Fedoraproject Fedora: 30, 31

How to fix

Upgrade to a fixed version: containers crun 0.10.5. Check the vendor advisory for mitigations.

References

https://github.com/containers/crun/pull/173
https://github.com/containers/crun/releases/tag/0.10.5
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DTA5SJUAKQUK6HRY2CZVJUIZP5BO3EOG/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ITB2UNEGHXZUR3ATYHWPSK5LJB36N7AP/
https://github.com/containers/crun/pull/173
https://github.com/containers/crun/releases/tag/0.10.5
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DTA5SJUAKQUK6HRY2CZVJUIZP5BO3EOG/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ITB2UNEGHXZUR3ATYHWPSK5LJB36N7AP/

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