CVE-2021-39685

Published: 16 December 2021

In various setup methods of the USB gadget subsystem, there is a possible out of bounds write due to an incorrect flag check. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-210292376References: Upstream kernel

From the Ubuntu security team

Szymon Heidrich discovered that the USB Gadget subsystem in the Linux kernel did not properly restrict the size of control requests for certain gadget types, leading to possible out of bounds reads or writes. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code.

Notes

likely introduces subtle regression that needs
f08adf5add9a ("USB: gadget: bRequestType is a bitfield, not a enum")
to address

Priority

Medium

CVSS 3 base score: 7.8

Status

References

• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-39685
• https://www.openwall.com/lists/oss-security/2021/12/15/4
• https://github.com/szymonh/inspector-gadget
• https://ubuntu.com/security/notices/USN-5278-1
• https://ubuntu.com/security/notices/USN-5294-1
• https://ubuntu.com/security/notices/USN-5294-2
• https://ubuntu.com/security/notices/USN-5297-1
• https://ubuntu.com/security/notices/USN-5298-1
• https://ubuntu.com/security/notices/USN-5337-1
• https://ubuntu.com/security/notices/USN-5368-1
• https://ubuntu.com/security/notices/USN-5505-1
• https://ubuntu.com/security/notices/USN-5513-1
• NVD
• Launchpad
• Debian