Vulnerability Description
XScreenSaver 5.45 can be bypassed if the machine has more than ten disconnectable video outputs. A buffer overflow in update_screen_layout() allows an attacker to bypass the standard screen lock authentication mechanism by crashing XScreenSaver. The attacker must physically disconnect many video outputs.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Xscreensaver Project | Xscreensaver | 5.45 |
| Fedoraproject | Fedora | 33 |
Related Weaknesses (CWE)
References
- http://www.openwall.com/lists/oss-security/2021/06/11/1Mailing ListThird Party Advisory
- http://www.openwall.com/lists/oss-security/2021/07/06/2ExploitMailing ListThird Party Advisory
- https://github.com/QubesOS/qubes-issues/issues/6595Issue TrackingThird Party Advisory
- https://github.com/QubesOS/qubes-secpack/blob/master/QSBs/qsb-068-2021.txtExploitThird Party Advisory
- https://github.com/QubesOS/qubes-xscreensaver/blob/master/0001-Fix-updating-outpPatchThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://www.openwall.com/lists/oss-security/2021/06/05/1ExploitMailing ListThird Party Advisory
- http://www.openwall.com/lists/oss-security/2021/06/11/1Mailing ListThird Party Advisory
- http://www.openwall.com/lists/oss-security/2021/07/06/2ExploitMailing ListThird Party Advisory
- https://github.com/QubesOS/qubes-issues/issues/6595Issue TrackingThird Party Advisory
- https://github.com/QubesOS/qubes-secpack/blob/master/QSBs/qsb-068-2021.txtExploitThird Party Advisory
- https://github.com/QubesOS/qubes-xscreensaver/blob/master/0001-Fix-updating-outpPatchThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://www.openwall.com/lists/oss-security/2021/06/05/1ExploitMailing ListThird Party Advisory
FAQ
What is CVE-2021-34557?
CVE-2021-34557 is a vulnerability with a CVSS score of 4.6 (MEDIUM). XScreenSaver 5.45 can be bypassed if the machine has more than ten disconnectable video outputs. A buffer overflow in update_screen_layout() allows an attacker to bypass the standard screen lock authe...
How severe is CVE-2021-34557?
CVE-2021-34557 has been rated MEDIUM with a CVSS base score of 4.6/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-34557?
Check the references section above for vendor advisories and patch information. Affected products include: Xscreensaver Project Xscreensaver, Fedoraproject Fedora.