{"containers":{"cna":{"affected":[{"product":"n/a","vendor":"n/a","versions":[{"status":"affected","version":"n/a"}]}],"descriptions":[{"lang":"en","value":"An issue was discovered in Xen through 4.14.x. There are missing memory barriers when accessing/allocating an event channel. Event channels control structures can be accessed lockless as long as the port is considered to be valid. Such a sequence is missing an appropriate memory barrier (e.g., smp_*mb()) to prevent both the compiler and CPU from re-ordering access. A malicious guest may be able to cause a hypervisor crash resulting in a Denial of Service (DoS). Information leak and privilege escalation cannot be excluded. Systems running all versions of Xen are affected. Whether a system is vulnerable will depend on the CPU and compiler used to build Xen. For all systems, the presence and the scope of the vulnerability depend on the precise re-ordering performed by the compiler used to build Xen. We have not been able to survey compilers; consequently we cannot say which compiler(s) might produce vulnerable code (with which code generation options). GCC documentation clearly suggests that re-ordering is possible. Arm systems will also be vulnerable if the CPU is able to re-order memory access. Please consult your CPU vendor. x86 systems are only vulnerable if a compiler performs re-ordering."}],"problemTypes":[{"descriptions":[{"description":"n/a","lang":"en","type":"text"}]}],"providerMetadata":{"dateUpdated":"2020-11-11T05:06:30.000Z","orgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","shortName":"mitre"},"references":[{"tags":["x_refsource_MISC"],"url":"https://xenbits.xen.org/xsa/advisory-340.html"},{"name":"FEDORA-2020-306b84fd07","tags":["vendor-advisory","x_refsource_FEDORA"],"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4JRXMKEMQRQYWYEPHVBIWUEAVQ3LU4FN/"},{"name":"FEDORA-2020-f668e579be","tags":["vendor-advisory","x_refsource_FEDORA"],"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DA633Y3G5KX7MKRN4PFEGM3IVTJMBEOM/"},{"name":"DSA-4769","tags":["vendor-advisory","x_refsource_DEBIAN"],"url":"https://www.debian.org/security/2020/dsa-4769"},{"name":"openSUSE-SU-2020:1608","tags":["vendor-advisory","x_refsource_SUSE"],"url":"http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00008.html"},{"name":"FEDORA-2020-d46fe34349","tags":["vendor-advisory","x_refsource_FEDORA"],"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RJZERRBJN6E6STDCHT4JHP4MI6TKBCJE/"},{"name":"GLSA-202011-06","tags":["vendor-advisory","x_refsource_GENTOO"],"url":"https://security.gentoo.org/glsa/202011-06"}],"x_legacyV4Record":{"CVE_data_meta":{"ASSIGNER":"cve@mitre.org","ID":"CVE-2020-25603","STATE":"PUBLIC"},"affects":{"vendor":{"vendor_data":[{"product":{"product_data":[{"product_name":"n/a","version":{"version_data":[{"version_value":"n/a"}]}}]},"vendor_name":"n/a"}]}},"data_format":"MITRE","data_type":"CVE","data_version":"4.0","description":{"description_data":[{"lang":"eng","value":"An issue was discovered in Xen through 4.14.x. 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Arm systems will also be vulnerable if the CPU is able to re-order memory access. 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