Description
An issue was discovered in Xen through 4.14.x. When they require assistance from the device model, x86 HVM guests must be temporarily de-scheduled. The device model will signal Xen when it has completed its operation, via an event channel, so that the relevant vCPU is rescheduled. If the device model were to signal Xen without having actually completed the operation, the de-schedule / re-schedule cycle would repeat. If, in addition, Xen is resignalled very quickly, the re-schedule may occur before the de-schedule was fully complete, triggering a shortcut. This potentially repeating process uses ordinary recursive function calls, and thus could result in a stack overflow. A malicious or buggy stubdomain serving a HVM guest can cause Xen to crash, resulting in a Denial of Service (DoS) to the entire host. Only x86 systems are affected. Arm systems are not affected. Only x86 stubdomains serving HVM guests can exploit the vulnerability.
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 | 4.14.0+88-g1d1d1f5391-1 | — |
| Debian 13 | xen | 4.14.0+88-g1d1d1f5391-1 | — |
| Debian 12 | xen | 4.14.0+88-g1d1d1f5391-1 | — |
| Debian 10 | xen | 4.11.4+57-g41a822c392-2 | DSA-4812-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | xen | No fix yet | — |
| Ubuntu 18.04 LTS | xen | No fix yet | — |
| Ubuntu 16.04 LTS | xen | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP2 | xen | 4.13.2_06-3.22.1 | SUSE-SU-2020:3915-1 |
| SLES 15 SP1 | xen | 4.12.4_06-3.40.1 | SUSE-SU-2020:3881-1 |
| SLES 12 SP5 | xen | 4.12.4_06-3.36.1 | SUSE-SU-2020:3880-1 |
| SLES 12 SP4 | xen | 4.11.4_16-2.48.1 | SUSE-SU-2020:3914-1 |
| SLES 12 SP3 | xen | 4.9.4_16-3.80.1 | SUSE-SU-2020:3945-1 |
Show 15 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP2 | xen | 4.7.6_14-43.73.1 | SUSE-SU-2020:3913-1 |
| SLES 11 SP4 | xen | 4.4.4_48-61.61.1 | SUSE-SU-2020:14578-1 |
| SLES for SAP 15 | xen | 4.10.4_24-3.53.1 | SUSE-SU-2020:3916-1 |
| SLES for SAP 12 SP5 | xen | 4.12.4_06-3.36.1 | SUSE-SU-2020:3880-1 |
| SLES for SAP 12 SP4 | xen | 4.11.4_16-2.48.1 | SUSE-SU-2020:3914-1 |
| SLES for SAP 12 SP3 | xen | 4.9.4_16-3.80.1 | SUSE-SU-2020:3945-1 |
| SLES for SAP 12 SP2 | xen | 4.7.6_14-43.73.1 | SUSE-SU-2020:3913-1 |
| SLE HPC 15 | xen | 4.10.4_24-3.53.1 | SUSE-SU-2020:3916-1 |
| SUSE OpenStack Cloud Crowbar 9 | xen | 4.11.4_16-2.48.1 | SUSE-SU-2020:3914-1 |
| SUSE OpenStack Cloud Crowbar 8 | xen | 4.9.4_16-3.80.1 | SUSE-SU-2020:3945-1 |
| SUSE OpenStack Cloud 9 | xen | 4.11.4_16-2.48.1 | SUSE-SU-2020:3914-1 |
| SUSE OpenStack Cloud 8 | xen | 4.9.4_16-3.80.1 | SUSE-SU-2020:3945-1 |
| SUSE OpenStack Cloud 7 | xen | 4.7.6_14-43.73.1 | SUSE-SU-2020:3913-1 |
| SUSE HPE Helion OpenStack 8 | xen | 4.9.4_16-3.80.1 | SUSE-SU-2020:3945-1 |
| SUSE Enterprise Storage 5 | xen | 4.9.4_16-3.80.1 | SUSE-SU-2020:3945-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | xen | 4.15.1_01-1.2 | openSUSE-SU-2024:11520-1 |
| openSUSE Leap 15.2 | xen | 4.13.2_06-lp152.2.21.1 | openSUSE-SU-2020:2331-1 |
| openSUSE Leap 15.1 | xen | 4.12.4_06-lp151.2.36.1 | openSUSE-SU-2020:2313-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | xen | 4.14.1-r0 | — |
| Alpine v3.23 | xen | 4.14.1-r0 | — |
| Alpine v3.22 | xen | 4.14.1-r0 | — |
| Alpine v3.21 | xen | 4.14.1-r0 | — |
| Alpine v3.20 | xen | 4.14.1-r0 | — |
Show 9 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | xen | 4.14.1-r0 | — |
| Alpine v3.18 | xen | 4.14.1-r0 | — |
| Alpine v3.17 | xen | 4.14.1-r0 | — |
| Alpine v3.16 | xen | 4.14.1-r0 | — |
| Alpine v3.15 | xen | 4.14.1-r0 | — |
| Alpine v3.14 | xen | 4.14.1-r0 | — |
| Alpine v3.13 | xen | 4.14.1-r0 | — |
| Alpine v3.12 | xen | 4.13.2-r3 | — |
| Alpine v3.11 | xen | 4.13.2-r3 | — |
Advisories 12
- DSA-4812-1 xen - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2020:3880-1 Security update for xen SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:3913-1 Security update for xen SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:14578-1 Security update for xen SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:3881-1 Security update for xen SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:2331-1 Security update for xen SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:3916-1 Security update for xen SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:3945-1 Security update for xen SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:3915-1 Security update for xen SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:3914-1 Security update for xen SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:2313-1 Security update for xen SUSE / openSUSE Security Updates · May 7, 2025
- openSUSE-SU-2024:11520-1 xen-4.15.1_01-1.2 on GA media SUSE / openSUSE Security Updates · May 7, 2025
References
- https://xenbits.xenproject.org/xsa/advisory-348.html
- DSA-4812 vendor-advisory
- FEDORA-2020-64859a826b vendor-advisory
- FEDORA-2020-df772b417b vendor-advisory
- GLSA-202107-30 vendor-advisory