Out-of-bounds Write Affecting linux-4.9 package, versions <4.9.168-1~deb8u1


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.07% (35th percentile)

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  • Snyk IDSNYK-DEBIAN8-LINUX49-345519
  • published3 Jan 2019
  • disclosed3 Jan 2019

Introduced: 3 Jan 2019

CVE-2019-3701  (opens in a new tab)
CWE-787  (opens in a new tab)

How to fix?

Upgrade Debian:8 linux-4.9 to version 4.9.168-1~deb8u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-4.9 package and not the linux-4.9 package as distributed by Debian. See How to fix? for Debian:8 relevant fixed versions and status.

An issue was discovered in can_can_gw_rcv in net/can/gw.c in the Linux kernel through 4.19.13. The CAN frame modification rules allow bitwise logical operations that can be also applied to the can_dlc field. The privileged user "root" with CAP_NET_ADMIN can create a CAN frame modification rule that makes the data length code a higher value than the available CAN frame data size. In combination with a configured checksum calculation where the result is stored relatively to the end of the data (e.g. cgw_csum_xor_rel) the tail of the skb (e.g. frag_list pointer in skb_shared_info) can be rewritten which finally can cause a system crash. Because of a missing check, the CAN drivers may write arbitrary content beyond the data registers in the CAN controller's I/O memory when processing can-gw manipulated outgoing frames.

CVSS Base Scores

version 3.1