Description
The DNS resolution functionality in the CIFS implementation in the Linux kernel before 2.6.35, when CONFIG_CIFS_DFS_UPCALL is enabled, relies on a user's keyring for the dns_resolver upcall in the cifs.upcall userspace helper, which allows local users to spoof the results of DNS queries and perform arbitrary CIFS mounts via vectors involving an add_key call, related to a "cache stuffing" issue and MS-DFS referrals.
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 | 2.6.26-26lenny3 | DSA-2264-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 5 | kernel +12 | 2.6.18-194.11.1.el5 | RHSA-2010:0610 |
Advisories 2
- RHSA-2010:0610 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- DSA-2264-1 linux-2.6 - several issues Debian Security (DSA / DLA) · Mar 9, 2026
References
- RHSA-2010:0610 vendor-advisory
- USN-1000-1 vendor-advisory
- [oss-security] 20100802 Re: CVE-2010-2524 kernel: dns_resolver upcall security issue mailing-list
- SUSE-SA:2010:040 vendor-advisory
- http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.35
- 43315 third-party-advisory
- [oss-security] 20100802 CVE-2010-2524 kernel: dns_resolver upcall security issue mailing-list
- http://www.vmware.com/security/advisories/VMSA-2011-0003.html
- https://bugzilla.redhat.com/show_bug.cgi?id=612166
- 20110211 VMSA-2011-0003 Third party component updates for VMware vCenter Server, vCenter Update Manager, ESXi and ESX mailing-list
- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=4c0c03ca54f72fdd5912516ad0a23ec5cf01bda7
- MDVSA-2010:172 vendor-advisory
- [oss-security] 20100803 Re: CVE-2010-2524 kernel: dns_resolver upcall security issue mailing-list