CVE-2021-28691

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Summary

CVECVE-2021-28691
StatePUBLISHED
AssignerXEN
Source PriorityCVE Program / NVD first with legacy fallback
Published2021-06-29 12:15:08 UTC
Updated2026-08-26 17:57:08 UTC
DescriptionGuest triggered use-after-free in Linux xen-netback A malicious or buggy network PV frontend can force Linux netback to disable the interface and terminate the receive kernel thread associated with queue 0 in response to the frontend sending a malformed packet. Such kernel thread termination will lead to a use-after-free in Linux netback when the backend is destroyed, as the kernel thread associated with queue 0 will have already exited and thus the call to kthread_stop will be performed against a stale pointer.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.003610000 probability, percentile 0.289250000 (date 2026-08-27)

Problem Types: CWE-416 | unknown

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
2.0[email protected]Primary4.6AV:L/AC:L/Au:N/C:P/I:P/A:P

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v2.0 Breakdown

Access Vector
Local
Access Complexity
Low
Authentication
None
Confidentiality
Partial
Integrity
Partial
Availability
Partial

AV:L/AC:L/Au:N/C:P/I:P/A:P

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All
Application Netapp Cloud Backup - All All All
Hardware Netapp H300e - All All All
Operating System Netapp H300e Firmware - All All All
Hardware Netapp H300s - All All All
Operating System Netapp H300s Firmware - All All All
Hardware Netapp H410c - All All All
Operating System Netapp H410c Firmware - All All All
Hardware Netapp H410s - All All All
Operating System Netapp H410s Firmware - All All All
Hardware Netapp H500e - All All All
Operating System Netapp H500e Firmware - All All All
Hardware Netapp H500s - All All All
Operating System Netapp H500s Firmware - All All All
Hardware Netapp H700e - All All All
Operating System Netapp H700e Firmware - All All All
Hardware Netapp H700s - All All All
Operating System Netapp H700s Firmware - All All All
Application Netapp Solidfire Baseboard Management Controller - All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux unknown unspecified 4.12 custom Not specified
CNA Linux Linux affected 5.5.0 unspecified custom Not specified
CNA Linux Linux unaffected next of 5.12.2 unspecified custom Not specified

References

ReferenceSourceLinkTags
xenbits.xenproject.org/xsa/advisory-374.txt af854a3a-2127-422b-91ae-364da2661108 xenbits.xenproject.org Third Party Advisory
CVE-2021-28691 Linux Kernel Vulnerability in NetApp Products | NetApp Product Security af854a3a-2127-422b-91ae-364da2661108 security.netapp.com Third Party Advisory
Xen: Multiple vulnerabilities (GLSA 202107-30) — Gentoo security af854a3a-2127-422b-91ae-364da2661108 security.gentoo.org Third Party Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: {'credit_data': {'description': {'description_data': [{'lang': 'eng', 'value': 'This issue was discovered by Michael Brown of iPXE and diagnosed by\nOlivier Benjamin, Michael Kurth and Martin Mazein of AWS.'}]}}} (en)

Legacy QID Mappings

  • 180071 Debian Security Update for linux (CVE-2021-28691)
  • 198436 Ubuntu Security Notification for Linux kernel (OEM) vulnerabilities (USN-5015-1) (Sequoia)
  • 198465 Ubuntu Security Notification for Linux kernel Vulnerabilities (USN-5046-1)
  • 198468 Ubuntu Security Notification for Linux kernel Vulnerabilities (USN-5050-1)
  • 353158 Amazon Linux Security Advisory for kernel : ALAS2KERNEL-5.10-2022-002
  • 710038 Gentoo Linux Xen Multiple vulnerabilities (GLSA 202107-30)
  • 900084 CBL-Mariner Linux Security Update for kernel 5.10.52.1
  • 900304 CBL-Mariner Linux Security Update for kernel 5.10.57.1
  • 900319 CBL-Mariner Linux Security Update for kernel 5.10.60.1
  • 900887 Common Base Linux Mariner (CBL-Mariner) Security Update for kernel (6537-1)
  • 903024 Common Base Linux Mariner (CBL-Mariner) Security Update for kernel (4375)
  • 906029 Common Base Linux Mariner (CBL-Mariner) Security Update for kernel (4375-1)

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