Description
The nullfs implementation in sys/fs/nullfs/null_vnops.c in the kernel in FreeBSD 8.3 through 9.2 allows local users with certain permissions to bypass access restrictions via a hardlink in a nullfs instance to a file in a different instance.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 7 | kfreebsd-9 | 9.0-10+deb70.4 | DSA-2769-1 |
Advisories 1
- DSA-2769-1 kfreebsd-9 - several Debian Security (DSA / DLA) · Mar 9, 2026
References
- 54861 third-party-advisory
- 1029015 vdb-entry
- DSA-2769 vendor-advisory
- FreeBSD-SA-13:13 vendor-advisory
- http://svnweb.freebsd.org/base?view=revision&revision=255442