PT-2021-8097 · Linux+2 · Linux Kernel+2
Xiaolong Huang
·
Published
2021-10-08
·
Updated
2024-09-18
·
CVE-2021-4439
CVSS v3.1
7.8
High
| Vector | AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
Name of the Vulnerable Software and Affected Versions
Linux kernel versions prior to 5.15.0-rc2+
Description
The vulnerability is related to an array index out of bounds bug in the
cmtp add connection function of the isdn component in the Linux kernel. This bug can be triggered when the detach capi ctr function is called to detach a register controller that is not attached yet. The vulnerability can cause a denial of service.Technical details about exploitation include:
- The
cmtp add connectionfunction adds a cmtp session to a controller and runs a kernel thread to process cmtp. - The kernel thread calls
detach capi ctrto detach a register controller, which can trigger the array-index-out-bounds bug if the controller is not attached yet. - The bug is caused by an index of -1 being out of range for the type
capi ctr *[32]. - The
detach capi ctrfunction is called bycmtp session, which is run by the kernel thread.
Recommendations
At the moment, there is no information about a newer version that contains a fix for this vulnerability.
Improper Validation of Array Index
Memory Corruption
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Related Identifiers
Affected Products
Astra Linux
Linux Kernel
Suse