CVE-2020-25601
Published: 23 September 2020
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.
Notes
| Author | Note |
|---|---|
| mdeslaur | hypervisor packages are in universe. For issues in the hypervisor, add appropriate tags to each section, ex: Tags_xen: universe-binary |
Priority
Status
| Package | Release | Status |
|---|---|---|
|
xen Launchpad, Ubuntu, Debian |
bionic |
Needed
|
| focal |
Released
(4.11.3+24-g14b62ab3e5-1ubuntu2.3)
|
|
| groovy |
Ignored
(reached end-of-life)
|
|
| hirsute |
Ignored
(reached end-of-life)
|
|
| impish |
Ignored
(reached end-of-life)
|
|
| jammy |
Not vulnerable
(4.11.4+37-g3263f257ca-1)
|
|
| kinetic |
Not vulnerable
(4.11.4+37-g3263f257ca-1)
|
|
| precise |
Does not exist
|
|
| trusty |
Does not exist
|
|
| upstream |
Needs triage
|
|
| xenial |
Needed
|
|
| Binaries built from this source package are in Universe and so are supported by the community. | ||
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 5.5 |
| Attack vector | Local |
| Attack complexity | Low |
| Privileges required | Low |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | None |
| Integrity impact | None |
| Availability impact | High |
| Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
References
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-25601
- https://xenbits.xen.org/xsa/advisory-344.html
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4JRXMKEMQRQYWYEPHVBIWUEAVQ3LU4FN/
- https://ubuntu.com/security/notices/USN-5617-1
- NVD
- Launchpad
- Debian