gss_mech_free in net/sunrpc/auth_gss/gss_mech_switch.c in the rpcsec_gss_krb5 implementation in the Linux kernel through 5.6.10 lacks certain domain_release calls, leading to a memory leak.

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-12656
• https://bugzilla.kernel.org/show_bug.cgi?id=206651
• http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00022.html
• http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00008.html
• https://usn.ubuntu.com/4483-1
• https://usn.ubuntu.com/4485-1