# CVE-2015-8550: libxencall1t64: Xen, when used on a system providing PV backends, allows local guest OSadministrators to cause a denial of service (h...

CVE-2015-8550 is fixed in 42 products on 1 platform, first by libxencall1t64 4.6.0-1ubuntu2, released December 17, 2015. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2015-8550
- Priority: Routine
- CVSS: n/a (Medium)
- EPSS: 0.0108
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Dec 17, 2015

## Description

Xen, when used on a system providing PV backends, allows local guest OSadministrators to cause a denial of service (host OS crash) or gainprivileges by writing to memory shared between the frontend and backend,aka a double fetch vulnerability.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libxencall1t64 Ubuntu 25.04 (plucky) | 4.6.0-1ubuntu2 | [libxencall1t64 4.6.0-1ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-libxencall1t64-4.6.0-1ubuntu2.md) | Dec 17, 2015 |
| Linux | libxendevicemodel1t64 Ubuntu 25.04 (plucky) | 4.6.0-1ubuntu2 | [libxendevicemodel1t64 4.6.0-1ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-libxendevicemodel1t64-4.6.0-1ubuntu2.md) | Dec 17, 2015 |
| Linux | libxenevtchn1t64 Ubuntu 25.04 (plucky) | 4.6.0-1ubuntu2 | [libxenevtchn1t64 4.6.0-1ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-libxenevtchn1t64-4.6.0-1ubuntu2.md) | Dec 17, 2015 |
| Linux | libxenforeignmemory1t64 Ubuntu 25.04 (plucky) | 4.6.0-1ubuntu2 | [libxenforeignmemory1t64 4.6.0-1ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-libxenforeignmemory1t64-4.6.0-1ubuntu2.md) | Dec 17, 2015 |
| Linux | libxengnttab1t64 Ubuntu 25.04 (plucky) | 4.6.0-1ubuntu2 | [libxengnttab1t64 4.6.0-1ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-libxengnttab1t64-4.6.0-1ubuntu2.md) | Dec 17, 2015 |
| Linux | libxenhypfs1t64 Ubuntu 25.04 (plucky) | 4.6.0-1ubuntu2 | [libxenhypfs1t64 4.6.0-1ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-libxenhypfs1t64-4.6.0-1ubuntu2.md) | Dec 17, 2015 |
| Linux | libxenmisc4.17t64 Ubuntu 25.04 (plucky) | 4.6.0-1ubuntu2 | [libxenmisc4.17t64 4.6.0-1ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-libxenmisc4.17t64-4.6.0-1ubuntu2.md) | Dec 17, 2015 |
| Linux | libxenstore4t64 Ubuntu 25.04 (plucky) | 4.6.0-1ubuntu2 | [libxenstore4t64 4.6.0-1ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-libxenstore4t64-4.6.0-1ubuntu2.md) | Dec 17, 2015 |
| Linux | libxentoolcore1t64 Ubuntu 25.04 (plucky) | 4.6.0-1ubuntu2 | [libxentoolcore1t64 4.6.0-1ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-libxentoolcore1t64-4.6.0-1ubuntu2.md) | Dec 17, 2015 |
| Linux | libxentoollog1t64 Ubuntu 25.04 (plucky) | 4.6.0-1ubuntu2 | [libxentoollog1t64 4.6.0-1ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-libxentoollog1t64-4.6.0-1ubuntu2.md) | Dec 17, 2015 |
| Linux | qemu-block-extra Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-block-extra 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-block-extra-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-block-supplemental Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-block-supplemental 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-block-supplemental-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-guest-agent Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-guest-agent 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-guest-agent-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-system Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-system 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-system-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-system-arm Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-system-arm 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-system-arm-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-system-common Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-system-common 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-system-common-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-system-data Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-system-data 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-system-data-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-system-gui Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-system-gui 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-system-gui-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-system-mips Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-system-mips 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-system-mips-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-system-misc Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-system-misc 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-system-misc-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-system-modules-opengl Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-system-modules-opengl 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-system-modules-opengl-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-system-modules-spice Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-system-modules-spice 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-system-modules-spice-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-system-ppc Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-system-ppc 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-system-ppc-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-system-s390x Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-system-s390x 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-system-s390x-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-system-sparc Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-system-sparc 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-system-sparc-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-system-x86 Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-system-x86 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-system-x86-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-system-x86-xen Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-system-x86-xen 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-system-x86-xen-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-system-xen Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-system-xen 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-system-xen-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-user Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-user 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-user-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-user-binfmt Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-user-binfmt 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-user-binfmt-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-user-static Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-user-static 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-user-static-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | qemu-utils Ubuntu 25.04 (plucky) | 1:2.5+dfsg-1ubuntu5 | [qemu-utils 1:2.5+dfsg-1ubuntu5](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-qemu-utils-1-2.5-dfsg-1ubuntu5.md) | Dec 17, 2015 |
| Linux | xen-hypervisor-4.17-amd64 Ubuntu 25.04 (plucky) | 4.6.0-1ubuntu2 | [xen-hypervisor-4.17-amd64 4.6.0-1ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-xen-hypervisor-4.17-amd64-4.6.0-1ubuntu2.md) | Dec 17, 2015 |
| Linux | xen-hypervisor-4.17-arm64 Ubuntu 25.04 (plucky) | 4.6.0-1ubuntu2 | [xen-hypervisor-4.17-arm64 4.6.0-1ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-xen-hypervisor-4.17-arm64-4.6.0-1ubuntu2.md) | Dec 17, 2015 |
| Linux | xen-hypervisor-4.17-armhf Ubuntu 25.04 (plucky) | 4.6.0-1ubuntu2 | [xen-hypervisor-4.17-armhf 4.6.0-1ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-xen-hypervisor-4.17-armhf-4.6.0-1ubuntu2.md) | Dec 17, 2015 |
| Linux | xen-hypervisor-common Ubuntu 25.04 (plucky) | 4.6.0-1ubuntu2 | [xen-hypervisor-common 4.6.0-1ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-xen-hypervisor-common-4.6.0-1ubuntu2.md) | Dec 17, 2015 |
| Linux | xen-system-amd64 Ubuntu 25.04 (plucky) | 4.6.0-1ubuntu2 | [xen-system-amd64 4.6.0-1ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-xen-system-amd64-4.6.0-1ubuntu2.md) | Dec 17, 2015 |
| Linux | xen-system-arm64 Ubuntu 25.04 (plucky) | 4.6.0-1ubuntu2 | [xen-system-arm64 4.6.0-1ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-xen-system-arm64-4.6.0-1ubuntu2.md) | Dec 17, 2015 |
| Linux | xen-system-armhf Ubuntu 25.04 (plucky) | 4.6.0-1ubuntu2 | [xen-system-armhf 4.6.0-1ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-xen-system-armhf-4.6.0-1ubuntu2.md) | Dec 17, 2015 |
| Linux | xen-utils-4.17 Ubuntu 25.04 (plucky) | 4.6.0-1ubuntu2 | [xen-utils-4.17 4.6.0-1ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-xen-utils-4.17-4.6.0-1ubuntu2.md) | Dec 17, 2015 |
| Linux | xen-utils-common Ubuntu 25.04 (plucky) | 4.6.0-1ubuntu2 | [xen-utils-common 4.6.0-1ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-xen-utils-common-4.6.0-1ubuntu2.md) | Dec 17, 2015 |
| Linux | xenstore-utils Ubuntu 25.04 (plucky) | 4.6.0-1ubuntu2 | [xenstore-utils 4.6.0-1ubuntu2](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-xenstore-utils-4.6.0-1ubuntu2.md) | Dec 17, 2015 |

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