Description
The nfs_can_extend_write function in fs/nfs/write.c in the Linux kernel before 3.13.3 relies on a write delegation to extend a write operation without a certain up-to-date verification, which allows local users to obtain sensitive information from kernel memory in opportunistic circumstances by writing to a file in an NFS filesystem and then reading the same file.
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 14 | linux | 3.13.4-1 | — |
| Debian 13 | linux | 3.13.4-1 | — |
| Debian 12 | linux | 3.13.4-1 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 6 | perf +16 | 2.6.32-431.11.2.el6 | RHSA-2014:0328 |
Advisories 1
- RHSA-2014:0328 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 28, 2026
References
- USN-2137-1 vendor-advisory
- USN-2140-1 vendor-advisory
- https://github.com/torvalds/linux/commit/263b4509ec4d47e0da3e753f85a39ea12d1eff24
- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=263b4509ec4d47e0da3e753f85a39ea12d1eff24
- [oss-security] 20140221 Re: Re: CVE request: Linux kernel: nfs: information leakage mailing-list
- http://www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.13.3
- https://bugzilla.redhat.com/show_bug.cgi?id=1066939