Description
The acceleration support for the "REP MOVS" instruction in Xen 4.4.x, 3.2.x, and earlier lacks properly bounds checking for memory mapped I/O (MMIO) emulated in the hypervisor, which allows local HVM guests to cause a denial of service (host crash) via unspecified vectors.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | xen | 4.4.1-5 | — |
| Debian 13 | xen | 4.4.1-5 | — |
| Debian 12 | xen | 4.4.1-5 | — |
| Debian 7 | xen | 4.1.4-3+deb7u4 | DSA-3140-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 14.04 LTS | xen | 4.4.1-0ubuntu0.14.04.2 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 5 | kernel +12 | 2.6.18-404.el5 | RHSA-2015:0783 |
Advisories 2
- RHSA-2015:0783 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- DSA-3140-1 xen - security update Debian Security (DSA / DLA) · Mar 9, 2026
References
- RHSA-2015:0783 vendor-advisory
- GLSA-201504-04 vendor-advisory
- 62672 third-party-advisory
- http://support.citrix.com/article/CTX201794
- http://support.citrix.com/article/CTX200288
- DSA-3140 vendor-advisory
- openSUSE-SU-2015:0226 vendor-advisory
- http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10705
- openSUSE-SU-2015:0256 vendor-advisory
- http://xenbits.xenproject.org/xsa/advisory-112.html
- 59949 third-party-advisory
- 71331 vdb-entry