Description
The start_authentication function in lightdm-gtk-greeter.c in LightDM GTK+ Greeter before 1.7.1 does not properly handle the return value from the lightdm_greeter_get_authentication_user function, which allows local users to cause a denial of service (NULL pointer dereference) via an empty username.
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 | lightdm-gtk-greeter | 1.6.1-5 | — |
| Debian 13 | lightdm-gtk-greeter | 1.6.1-5 | — |
| Debian 12 | lightdm-gtk-greeter | 1.6.1-5 | — |
References
- 64679 vdb-entry
- FEDORA-2014-1648 vendor-advisory
- https://bugzilla.novell.com/show_bug.cgi?id=857303
- [oss-security] 20140107 Re: CVE request: lightdm-gtk-greeter - local DOS due to NULL pointer dereference mailing-list
- FEDORA-2014-1647 vendor-advisory
- openSUSE-SU-2014:0071 vendor-advisory
- 56211 third-party-advisory
- https://bugs.launchpad.net/lightdm-gtk-greeter/+bug/1266449
- 56423 third-party-advisory