Bug 1928716 (CVE-2020-27066) - CVE-2020-27066 kernel: use after free in xfrm6_tunnel_free_spi of net/ipv6/xfrm6_tunnel.c leads to local escalation of privilege
Summary: CVE-2020-27066 kernel: use after free in xfrm6_tunnel_free_spi of net/ipv6/xf...
Keywords:
Status: CLOSED NOTABUG
Alias: CVE-2020-27066
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1928717
Blocks: 1928718
TreeView+ depends on / blocked
 
Reported: 2021-02-15 12:46 UTC by Marian Rehak
Modified: 2021-04-13 15:59 UTC (History)
42 users (show)

Fixed In Version:
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Doc Text:
A flaw was found in the Linux kernel. There is a possible use after free due to improper locking. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.
Clone Of:
Environment:
Last Closed: 2021-04-06 17:35:39 UTC
Embargoed:

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Description Marian Rehak 2021-02-15 12:46:23 UTC 
In xfrm6_tunnel_free_spi of net/ipv6/xfrm6_tunnel.c, there is a possible use after free due to improper locking. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.

External Reference:

https://source.android.com/security/bulletin/pixel/2020-12-01
https://www.linuxkernelcves.com/cves/CVE-2020-27066
Comment 1 Marian Rehak 2021-02-15 12:47:08 UTC 
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1928717]
Comment 5 Alex 2021-04-01 09:54:23 UTC 
Statement:

This flaw is rated as having Low impact because of the need to have elevated privileges and both configuration with the usage of IPV6.
Comment 6 Alex 2021-04-01 09:57:52 UTC 
Mitigation:

To mitigate this issue, prevent the module xfrm6_tunnel from being loaded.
Please see https://access.redhat.com/solutions/41278 for information on how to blacklist a kernel module to prevent it from loading automatically.
Comment 7 Product Security DevOps Team 2021-04-06 17:35:39 UTC 
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2020-27066
Comment 8 Justin M. Forbes 2021-04-13 15:59:13 UTC 
This was fixed for Fedora with the 5.5.14 stable kernel updates.
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