# CVE-2020-25601: libxengnttab1: An issue was discovered in Xen through 4.14.x CVE-2020-25601 is fixed in 22 products on 1 platform, first by libxencall1 4.11.3+24-g14b62ab3e5-1ubuntu2.3, released September 23, 2020. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2020-25601 - Priority: Routine - CVSS: n/a (Medium) - EPSS: 0.0042 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Sep 23, 2020 ## Description An issue was discovered in Xen through 4.14.x. There is a lack of preemption in evtchn_reset() / evtchn_destroy(). In particular, the FIFO event channel model allows guests to have a large number of event channels active at a time. Closing all of these (when resetting all event channels or when cleaning up after the guest) may take extended periods of time. So far, there was no arrangement for preemption at suitable intervals, allowing a CPU to spend an almost unbounded amount of time in the processing of these operations. Malicious or buggy guest kernels can mount a Denial of Service (DoS) attack affecting the entire system. All Xen versions are vulnerable in principle. Whether versions 4.3 and older are vulnerable depends on underlying hardware characteristics. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | libxencall1 Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [libxencall1 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libxencall1-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | libxendevicemodel1 Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [libxendevicemodel1 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libxendevicemodel1-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | libxenevtchn1 Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [libxenevtchn1 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libxenevtchn1-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | libxenforeignmemory1 Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [libxenforeignmemory1 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libxenforeignmemory1-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | libxengnttab1 Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [libxengnttab1 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libxengnttab1-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | libxenmisc4.11 Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [libxenmisc4.11 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libxenmisc4.11-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | libxenstore3.0 Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [libxenstore3.0 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libxenstore3.0-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | libxentoolcore1 Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [libxentoolcore1 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libxentoolcore1-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | libxentoollog1 Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [libxentoollog1 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libxentoollog1-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | xen-hypervisor-4.11-amd64 Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [xen-hypervisor-4.11-amd64 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xen-hypervisor-4.11-amd64-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | xen-hypervisor-4.11-arm64 Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [xen-hypervisor-4.11-arm64 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xen-hypervisor-4.11-arm64-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | xen-hypervisor-4.11-armhf Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [xen-hypervisor-4.11-armhf 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xen-hypervisor-4.11-armhf-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | xen-hypervisor-4.9-amd64 Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [xen-hypervisor-4.9-amd64 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xen-hypervisor-4.9-amd64-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | xen-hypervisor-4.9-arm64 Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [xen-hypervisor-4.9-arm64 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xen-hypervisor-4.9-arm64-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | xen-hypervisor-4.9-armhf Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [xen-hypervisor-4.9-armhf 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xen-hypervisor-4.9-armhf-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | xen-hypervisor-common Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [xen-hypervisor-common 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xen-hypervisor-common-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | xen-system-amd64 Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [xen-system-amd64 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xen-system-amd64-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | xen-system-arm64 Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [xen-system-arm64 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xen-system-arm64-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | xen-system-armhf Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [xen-system-armhf 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xen-system-armhf-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | xen-utils-4.11 Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [xen-utils-4.11 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xen-utils-4.11-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | xen-utils-common Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [xen-utils-common 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xen-utils-common-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | | Linux | xenstore-utils Ubuntu 20.04 LTS (focal) | 4.11.3+24-g14b62ab3e5-1ubuntu2.3 | [xenstore-utils 4.11.3+24-g14b62ab3e5-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-xenstore-utils-4.11.3-24-g14b62ab3e5-1ubuntu2.3.md) | Sep 23, 2020 | --- Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.