CVE-2020-25604: Race Condition
First published: Wed Sep 23 2020(Updated: )
An issue was discovered in Xen through 4.14.x. There is a race condition when migrating timers between x86 HVM vCPUs. When migrating timers of x86 HVM guests between its vCPUs, the locking model used allows for a second vCPU of the same guest (also operating on the timers) to release a lock that it didn't acquire. The most likely effect of the issue is a hang or crash of the hypervisor, i.e., a Denial of Service (DoS). All versions of Xen are affected. Only x86 systems are vulnerable. Arm systems are not vulnerable. Only x86 HVM guests can leverage the vulnerability. x86 PV and PVH cannot leverage the vulnerability. Only guests with more than one vCPU can exploit the vulnerability.
Credit: cve@mitre.org cve@mitre.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Xen Xen | <=4.14.0 | |
| Fedoraproject Fedora | =31 | |
| Fedoraproject Fedora | =32 | |
| Fedoraproject Fedora | =33 | |
| Debian Debian Linux | =10.0 | |
| openSUSE Leap | =15.2 | |
| debian/xen | 4.14.6-1 4.14.5+94-ge49571868d-1 4.17.3+10-g091466ba55-1~deb12u1 4.17.3+36-g54dacb5c02-1 |
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Reference Links
- http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00008.html
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4JRXMKEMQRQYWYEPHVBIWUEAVQ3LU4FN/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DA633Y3G5KX7MKRN4PFEGM3IVTJMBEOM/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RJZERRBJN6E6STDCHT4JHP4MI6TKBCJE/
- https://security.gentoo.org/glsa/202011-06
- https://www.debian.org/security/2020/dsa-4769
- https://xenbits.xen.org/xsa/advisory-336.html
- https://launchpad.net/bugs/cve/CVE-2020-25604
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4JRXMKEMQRQYWYEPHVBIWUEAVQ3LU4FN/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DA633Y3G5KX7MKRN4PFEGM3IVTJMBEOM/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RJZERRBJN6E6STDCHT4JHP4MI6TKBCJE/
- https://security-tracker.debian.org/tracker/CVE-2020-25604
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-25604
- https://nvd.nist.gov/vuln/detail/CVE-2020-25604
- https://ubuntu.com/security/CVE-2020-25604
Frequently Asked Questions
What is CVE-2020-25604?
CVE-2020-25604 is a vulnerability in Xen through version 4.14.x that allows for a race condition when migrating timers between x86 HVM vCPUs.
What is the impact of CVE-2020-25604?
The impact of CVE-2020-25604 is that a second vCPU of the same guest operating on the timers can release a lock, leading to a race condition.
Which software versions are affected by CVE-2020-25604?
The affected software versions include Xen 4.11.3+24- and Xen 4.11.4+107-gef32c7afa2-1, 4.14.5+94-ge49571868d-1, 4.17.1+2-gb773c48e36-1, and 4.17.2-1.
How can I fix CVE-2020-25604?
To fix CVE-2020-25604, you should update Xen to version 4.11.3+24- or apply the specific remedies provided for other affected software versions.
Where can I find more information about CVE-2020-25604?
You can find more information about CVE-2020-25604 on the Xen website at https://xenbits.xen.org/xsa/advisory-336.html.
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