Description
nfsd in the Linux kernel before 2.6.28.9 does not drop the CAP_MKNOD capability before handling a user request in a thread, which allows local users to create device nodes, as demonstrated on a filesystem that has been exported with the root_squash option.
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 5.0 | linux-2.6 | 2.6.26-15lenny2 | DSA-1800-1 |
| Debian 5.0 | user-mode-linux | 2.6.26-1um-2+15lenny2 | DSA-1800-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 5 | kernel +12 | 2.6.18-128.1.14.el5 | RHSA-2009:1106 |
| RHEL 4 | kernel +10 | 2.6.9-89.0.3.EL | RHSA-2009:1132 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat MRG 1 | kernel-rt +9 | 2.6.24.7-117.el5rt | RHSA-2009:1081 |
Advisories 4
- RHSA-2009:1132 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- RHSA-2009:1106 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- RHSA-2009:1081 Red Hat Security Advisory: kernel-rt security and bug fix update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- DSA-1800-1 linux-2.6 user-mode-linux - several vulnerabilities Debian Security (DSA / DLA) · Mar 9, 2026
References
- 35390 third-party-advisory
- 34432 third-party-advisory
- 34422 third-party-advisory
- ADV-2009-0802 vdb-entry
- 34786 third-party-advisory
- [oss-security] 20090323 CVE request: kernel: nfsd did not drop CAP_MKNOD for non-root mailing-list
- 34205 vdb-entry
- SUSE-SA:2009:028 vendor-advisory
- 37471 third-party-advisory
- 35656 third-party-advisory
- http://www.vmware.com/security/advisories/VMSA-2009-0016.html
- [linux-kernel] 20090311 VFS, NFS security bug? Should CAP_MKNOD and CAP_LINUX_IMMUTABLE be added to CAP_FS_MASK? mailing-list
- SUSE-SA:2009:030 vendor-advisory
- 35185 third-party-advisory
- oval:org.mitre.oval:def:10314 vdb-entry signature
- 20091120 VMSA-2009-0016 VMware vCenter and ESX update release and vMA patch release address multiple security issue in third party components mailing-list
- oval:org.mitre.oval:def:8382 vdb-entry signature
- SUSE-SA:2009:031 vendor-advisory
- SUSE-SA:2009:021 vendor-advisory
- USN-793-1 vendor-advisory
- RHSA-2009:1081 vendor-advisory
- DSA-1800 vendor-advisory
- 35343 third-party-advisory
- http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.28.9
- linux-kernel-capmknod-security-bypass(49356) vdb-entry
- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commitdiff%3Bh=76a67ec6fb79ff3570dcb5342142c16098299911
- 35121 third-party-advisory
- ADV-2009-3316 vdb-entry
- 35394 third-party-advisory