Bug 1927007 (CVE-2021-20181) - CVE-2021-20181 qemu: 9pfs: TOCTOU privilege escalation vulnerability
Summary: CVE-2021-20181 qemu: 9pfs: TOCTOU privilege escalation vulnerability
Keywords:
Status: CLOSED NOTABUG
Alias: CVE-2021-20181
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1927009 1927008
Blocks: 1927010 1928051
TreeView+ depends on / blocked
 
Reported: 2021-02-09 20:14 UTC by Guilherme de Almeida Suckevicz
Modified: 2024-03-20 10:30 UTC (History)
34 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
A race condition flaw was found in the 9pfs server implementation of QEMU. This flaw allows a malicious 9p client to cause a use-after-free error, potentially escalating their privileges on the system. The highest threat from this vulnerability is to confidentiality, integrity as well as system availability.
Clone Of:
Environment:
Last Closed: 2021-02-10 10:09:44 UTC
Embargoed:

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Description Guilherme de Almeida Suckevicz 2021-02-09 20:14:51 UTC 
A flaw was found in QEMU in the way it handles a list of open file descriptors. Improper synchronization of this list can lead to a use-after-free.

Reference:
https://bugs.launchpad.net/qemu/+bug/1911666

Upstream patch:
https://git.qemu.org/?p=qemu.git;a=commit;h=89fbea8737e8f7b954745a1ffc4238d377055305
Comment 1 Guilherme de Almeida Suckevicz 2021-02-09 20:15:23 UTC 
Created qemu tracking bugs for this issue:

Affects: epel-7 [bug 1927009]
Affects: fedora-all [bug 1927008]
Comment 2 Mauro Matteo Cascella 2021-02-10 09:51:35 UTC 
External References:

https://bugs.launchpad.net/qemu/+bug/1911666
Comment 3 Product Security DevOps Team 2021-02-10 10:09:44 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-2021-20181
Comment 4 Mauro Matteo Cascella 2021-02-10 10:46:44 UTC 
Statement:

This issue does not affect the versions of `qemu-kvm` as shipped with Red Hat products, as they do not include support for the virtio 9p backend.
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