Xen up to 4.13.x event-channel Port Allocation exceptional condition

Summaryinfo

A vulnerability classified as critical has been found in Xen up to 4.13.x. This affects an unknown function of the component event-channel Port Allocation. Performing a manipulation results in exceptional condition. This vulnerability is reported as CVE-2020-15566. The attack requires a local approach. No exploit exists.

Detailsinfo

A vulnerability, which was classified as critical, was found in Xen up to 4.13.x (Virtualization Software). This affects some unknown processing of the component event-channel Port Allocation. The manipulation with an unknown input leads to a exceptional condition vulnerability. CWE is classifying the issue as CWE-755. The product does not handle or incorrectly handles an exceptional condition. This is going to have an impact on availability. The summary by CVE is:

An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a host OS crash because of incorrect error handling in event-channel port allocation. The allocation of an event-channel port may fail for multiple reasons: (1) port is already in use, (2) the memory allocation failed, or (3) the port we try to allocate is higher than what is supported by the ABI (e.g., 2L or FIFO) used by the guest or the limit set by an administrator (max_event_channels in xl cfg). Due to the missing error checks, only (1) will be considered an error. All the other cases will provide a valid port and will result in a crash when trying to access the event channel. When the administrator configured a guest to allow more than 1023 event channels, that guest may be able to crash the host. When Xen is out-of-memory, allocation of new event channels will result in crashing the host rather than reporting an error. Xen versions 4.10 and later are affected. All architectures are affected. The default configuration, when guests are created with xl/libxl, is not vulnerable, because of the default event-channel limit.

The weakness was disclosed 07/07/2020 (oss-sec). The advisory is shared at openwall.com. This vulnerability is uniquely identified as CVE-2020-15566 since 07/06/2020. An attack has to be approached locally. No form of authentication is needed for exploitation. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/08/2020).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The entries VDB-157738, VDB-157736, VDB-157735 and VDB-157734 are pretty similar. Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Virtualization Software

Name

• Xen

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4
• 4.5
• 4.6
• 4.7
• 4.8
• 4.9
• 4.10
• 4.11
• 4.12
• 4.13

License

• open-source

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CPE 2.2info

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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