X.Org server security advisory: December 1, 2020

Matthieu Herrb matthieu at herrb.eu
Tue Dec 1 15:13:19 UTC 2020

X.Org server security advisory: December 1, 2020

Multiple input validation failures in X server XKB extension

These issues can lead to privileges elevations for authorized clients
on systems where the X server is running privileged.

* CVE-2020-14360 / ZDI CAN 11572 XkbSetMap Out-Of-Bounds Access

Insufficient checks on the lengths of the XkbSetMap request can lead to
out of bounds memory accesses in the X server.

* CVE-2020-25712 / ZDI-CAN-11839 XkbSetDeviceInfo Heap-based Buffer Overflow

Insufficient checks on input of the XkbSetDeviceInfo request can lead
to a buffer overflow on the head in the X server.


Patches for these issues have been committed to the xorg server git
repository. xorg-server 1.20.10 will be released shortly and will
include these patches.


commit 446ff2d3177087b8173fa779fa5b77a2a128988b

    Check SetMap request length carefully.
    Avoid out of bounds memory accesses on too short request.

    ZDI-CAN 11572 /  CVE-2020-14360

commit 87c64fc5b0db9f62f4e361444f4b60501ebf67b9

    Fix XkbSetDeviceInfo() and SetDeviceIndicators() heap overflows

    ZDI-CAN 11389 / CVE-2020-25712


These vulnerabilities have been discovered by Jan-Niklas Sohn working
with Trend Micro Zero Day Initiative.

Matthieu Herrb

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