FreeBSD's crontab calculates the MD5 sum of the previous and new cronjob to determine if any changes have been made before copying the new version in. In particular, it uses the MD5File() function, which takes a pathname as an argument, and is called with euid 0. A race condition in this process may lead to an arbitrary MD5 comparison regardless of the read permissions.

References

• https://nvd.nist.gov/vuln/detail/CVE-2011-1075
• https://marc.info/?l=full-disclosure&m=129891323028897&w=2
• https://security.netapp.com/advisory/ntap-20211125-0004/
• https://www.openwall.com/lists/oss-security/2011/02/28/14