CVE-2020-27786

A flaw was found in the Linux kernel’s implementation of MIDI, where an attacker with a local account and the permissions to issue ioctl commands to midi devices could trigger a use-after-free issue. A write to this specific memory while freed and before use causes the flow of execution to change and possibly allow for memory corruption or privilege escalation. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• http://www.openwall.com/lists/oss-security/2020/12/03/1
• https://bugzilla.redhat.com/show_bug.cgi?id=1900933
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c1f6e3c818dd734c30f6a7eeebf232ba2cf3181d
• https://security.netapp.com/advisory/ntap-20210122-0002/
• http://www.openwall.com/lists/oss-security/2020/12/03/1
• https://bugzilla.redhat.com/show_bug.cgi?id=1900933
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c1f6e3c818dd734c30f6a7eeebf232ba2cf3181d
• https://security.netapp.com/advisory/ntap-20210122-0002/