CVE-2021-27379
An issue was discovered in Xen through 4.11.x, allowing x86 Intel HVM guest OS users to achieve...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
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.
- Record
CVE-2021-27379- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 5.9 Medium
AV:L/AC:M/Au:N/C:P/I:P/A:C - Updated
- 2026-11-02
CVE ListNo score
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.
- Record
CVE-2021-27379- Updated
- 2026-11-02
EUVDEUVD-2021-14134No score
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.
- Record
EUVD-2021-14134- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-f444-f4gw-jhg6
An issue was discovered in Xen through 4.11.x, allowing x86 Intel HVM guest OS users to achieve...
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.
- Record
GHSA-f444-f4gw-jhg6- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-269
- Updated
- 2026-11-02
OSV
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.
- Record
CVE-2021-27379- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVDEBIAN-CVE-2021-27379
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.
- Record
DEBIAN-CVE-2021-27379- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Show 5 moreShow less
OSVUBUNTU-CVE-2021-27379
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.
- Record
UBUNTU-CVE-2021-27379- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVSUSE-SU-2021:1250-1No score
Security update for xen
This update for xen fixes the following issues:
- CVE-2021-27379: Fixed an issue where entries in the IOMMU were not being updated under certain circumstances due to improper backport of XSA-321 (XSA-366, bsc#1182431)
- Record
SUSE-SU-2021:1250-1- Updated
- 2026-11-02
OSVSUSE-SU-2021:1251-1No score
Security update for xen
This update for xen fixes the following issues:
- CVE-2021-27379: Fixed an issue where entries in the IOMMU were not being updated under certain circumstances due to improper backport of XSA-321 (XSA-366, bsc#1182431)
- CVE-2021-20257: Fixed an infinite loop in the e1000 NIC emulator (bsc#1182846)
- Record
SUSE-SU-2021:1251-1- Updated
- 2026-11-02
OSVSUSE-SU-2021:1252-1No score
Security update for xen
This update for xen fixes the following issues:
- CVE-2021-20257: xen: infinite loop issue in the e1000 NIC emulator (bsc#1182846).
- CVE-2021-27379: Fixed an issue where entries in the IOMMU were not being updated under certain circumstances due to improper backport of XSA-321 (XSA-366, bsc#1182431).
- Record
SUSE-SU-2021:1252-1- Updated
- 2026-11-02
OSVSUSE-SU-2021:1268-1No score
Security update for xen
This update for xen fixes the following issues:
- CVE-2021-27379: Fixed an issue where entries in the IOMMU were not being updated under certain circumstances due to improper backport of XSA-321 (XSA-366, bsc#1182431)
- Fixed an issue where xenstored was crashing with segfault (bsc#1182155).
- Record
SUSE-SU-2021:1268-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
xenDebian:12 | before 4.14.0+80-gd101b417b7-1 | 4.14.0+80-gd101b417b7-1 |
xenDebian:13 | before 4.14.0+80-gd101b417b7-1 | 4.14.0+80-gd101b417b7-1 |
xenDebian:14 | before 4.14.0+80-gd101b417b7-1 | 4.14.0+80-gd101b417b7-1 |
xenDebian:10 From an advisory covering 2 CVEs | before 4.11.4+99-g8bce4698f6-1, plus listed versions 4.11.1+92-g6c33308a8d-24.11.3+24-g14b62ab3e5-14.11.3+24-g14b62ab3e5-1~deb10u14.11.4+24-gddaaccbbab-14.11.4+24-gddaaccbbab-1~deb10u1 Show 4 moreShow less4.11.4+37-g3263f257ca-14.11.4+57-g41a822c392-14.11.4+57-g41a822c392-24.11.4-1 | 4.11.4+99-g8bce4698f6-1 |
xenSUSE:Linux Enterprise High Performance Computing 15-ESPOS | before 4.10.4_24-3.56.1 | 4.10.4_24-3.56.1 |
xenSUSE:Linux Enterprise High Performance Computing 15-LTSS | before 4.10.4_24-3.56.1 | 4.10.4_24-3.56.1 |
xenSUSE:Linux Enterprise Server for SAP Applications 15 | before 4.10.4_24-3.56.1 | 4.10.4_24-3.56.1 |
xenSUSE:OpenStack Cloud 9 From an advisory covering 2 CVEs | before 4.11.4_16-2.51.1 | 4.11.4_16-2.51.1 |
xenSUSE:OpenStack Cloud Crowbar 9 From an advisory covering 2 CVEs | before 4.11.4_16-2.51.1 | 4.11.4_16-2.51.1 |
xenSUSE:Linux Enterprise Server for SAP Applications 12 SP4 From an advisory covering 2 CVEs | before 4.11.4_16-2.51.1 | 4.11.4_16-2.51.1 |
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| Package | Affected | Fixed |
|---|---|---|
xenSUSE:Linux Enterprise Server 12 SP4-LTSS From an advisory covering 2 CVEs | before 4.11.4_16-2.51.1 | 4.11.4_16-2.51.1 |
xenSUSE:HPE Helion OpenStack 8 From an advisory covering 2 CVEs | before 4.9.4_16-3.83.1 | 4.9.4_16-3.83.1 |
xenSUSE:OpenStack Cloud 8 From an advisory covering 2 CVEs | before 4.9.4_16-3.83.1 | 4.9.4_16-3.83.1 |
xenSUSE:OpenStack Cloud Crowbar 8 From an advisory covering 2 CVEs | before 4.9.4_16-3.83.1 | 4.9.4_16-3.83.1 |
xenSUSE:Linux Enterprise Server for SAP Applications 12 SP3 From an advisory covering 2 CVEs | before 4.9.4_16-3.83.1 | 4.9.4_16-3.83.1 |
xenSUSE:Linux Enterprise Server 12 SP3-LTSS From an advisory covering 2 CVEs | before 4.9.4_16-3.83.1 | 4.9.4_16-3.83.1 |
xenSUSE:Linux Enterprise Server 12 SP3-BCL From an advisory covering 2 CVEs | before 4.9.4_16-3.83.1 | 4.9.4_16-3.83.1 |
xenSUSE:OpenStack Cloud 7 | before 4.7.6_14-43.76.1 | 4.7.6_14-43.76.1 |
xenSUSE:Linux Enterprise Server 12 SP2-BCL | before 4.7.6_14-43.76.1 | 4.7.6_14-43.76.1 |
xenUbuntu:16.04:LTS | All versions, plus listed versions 4.5.1-0ubuntu14.5.1-0ubuntu24.6.0-1ubuntu14.6.0-1ubuntu24.6.0-1ubuntu4 Show 7 moreShow less4.6.0-1ubuntu4.14.6.0-1ubuntu4.24.6.0-1ubuntu4.34.6.5-0ubuntu14.6.5-0ubuntu1.14.6.5-0ubuntu1.24.6.5-0ubuntu1.4 | None known |
xenUbuntu:18.04:LTS | All versions, plus listed versions 4.9.0-0ubuntu34.9.0-0ubuntu44.9.2-0ubuntu1 | None known |
xenUbuntu:20.04:LTS | All versions, plus listed versions 4.9.2-0ubuntu24.9.2-0ubuntu64.9.2-0ubuntu74.11.3+24-g14b62ab3e5-1ubuntu14.11.3+24-g14b62ab3e5-1ubuntu24.11.3+24-g14b62ab3e5-1ubuntu2.24.11.3+24-g14b62ab3e5-1ubuntu2.3 | None known |
xenUbuntu:22.04:LTS | All versions, plus listed versions 4.11.4+24-gddaaccbbab-1ubuntu24.16.0-1~ubuntu24.16.0-1~ubuntu2.1 | None known |
xenUbuntu:24.04:LTS | All versions, plus listed versions 4.17.2-14.17.2+55-g0b56bed864-14.17.2+76-ge1f9cb16e2-14.17.2+76-ge1f9cb16e2-1ubuntu14.17.3+10-g091466ba55-14.17.3+10-g091466ba55-1.1ubuntu24.17.3+10-g091466ba55-1.1ubuntu3 | None known |
xenUbuntu:25.10 | All versions, plus listed versions 4.20.0-1ubuntu14.20.0+68-g35cb38b222-1 | None known |
xenUbuntu:26.10 | All versions, plus listed versions 4.20.2+7-g1badcf5035-2build24.20.2+37-g61ff35323e-1ubuntu14.20.3+127-gc42374a105-1 | None known |
xenUbuntu:26.04:LTS | All versions, plus listed versions 4.20.0+68-g35cb38b222-14.20.2+7-g1badcf5035-24.20.2+7-g1badcf5035-2build2 | None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-27379 is a high vulnerability (CVSS 7.8) in Xen, published February 18, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.36%, the 29th percentile. Fixed in xen 4.14.0+80-gd101b417b7-1.
References
xenbits.xen.org/xsa/advisory-366.html
openwall.com/lists/oss-security/2021/02/23/1
debian.org/security/2021/dsa-4888
nvd.nist.gov/vuln/detail/CVE-2021-27379
github.com/advisories/GHSA-f444-f4gw-jhg6
security-tracker.debian.org/tracker/CVE-2021-27379
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suse.com/support/update/announcement/2021/suse-su-20211250-1
bugzilla.suse.com/1178591
ubuntu.com/security/CVE-2021-27379
cve.org/CVERecord?id=CVE-2021-27379