Vulnerability · Published Feb 18, 2021 · Assigned by mitre
CVE-2021-27379
High 7.8
In plain English
A high-severity security flaw in the xen package (Debian). There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 29% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS NVD)7.8High
Exploit odds (30 days)0.4%top 70.5% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known
Official description
An issue was discovered in Xen through 4.11.x, allowing x86 Intel HVM guest OS users to achieve unintended read/write DMA access, and possibly cause a denial of service (host OS crash) or gain privileges. This occurs because a backport missed a flush, and thus IOMMU updates were not always correct. NOTE: this issue exists because of an incomplete fix for CVE-2020-15565.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | xen | 4.14.0+80-gd101b417b7-1 | DEBIAN-CVE-2021-27379 |
| Debian:13 | xen | 4.14.0+80-gd101b417b7-1 | DEBIAN-CVE-2021-27379 |
| Debian:14 | xen | 4.14.0+80-gd101b417b7-1 | DEBIAN-CVE-2021-27379 |
| Ubuntu:22.04:LTS | xen | no fix listed | UBUNTU-CVE-2021-27379 |
| Ubuntu:24.04:LTS | xen | no fix listed | UBUNTU-CVE-2021-27379 |
| Ubuntu:25.10 | xen | no fix listed | UBUNTU-CVE-2021-27379 |
| Ubuntu:26.04:LTS | xen | no fix listed | UBUNTU-CVE-2021-27379 |
| Ubuntu:26.10 | xen | no fix listed | UBUNTU-CVE-2021-27379 |
Affected products (as reported)
References
- http://xenbits.xen.org/xsa/advisory-366.html x_refsource_CONFIRM
- https://xenbits.xen.org/xsa/advisory-366.html x_refsource_MISC
- [oss-security] 20210223 Xen Security Advisory 366 v2 (CVE-2021-27379) - missed flush in XSA-321 backport mailing-list, x_refsource_MLIST
- DSA-4888 vendor-advisory, x_refsource_DEBIAN