Description
An issue was discovered in Xen through 4.14.x. Some OSes (such as Linux, FreeBSD, and NetBSD) are processing watch events using a single thread. If the events are received faster than the thread is able to handle, they will get queued. As the queue is unbounded, a guest may be able to trigger an OOM in the backend. All systems with a FreeBSD, Linux, or NetBSD (any version) dom0 are vulnerable.
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 | linux | 5.9.15-1 | — |
| Debian 13 | linux | 5.9.15-1 | — |
| Debian 12 | linux | 5.9.15-1 | — |
| Debian 10 | linux | 4.19.171-2 | DSA-4843-1 |
| Debian 9 | linux | 4.9.258-1 | DLA-2586-1 |
| Debian 9 | linux-4.19 | 4.19.171-2~deb9u1 | DLA-2557-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | linux-raspi-realtime | No fix yet | — |
| Ubuntu 22.04 LTS | linux-realtime +1 | No fix yet | — |
| Ubuntu 20.04 LTS | linux | 5.4.0-66.74 | USN-4750-1 |
| Ubuntu 20.04 LTS | linux-aws | 5.4.0-1038.40 | USN-4750-1 |
| Ubuntu 20.04 LTS | linux-azure | 5.4.0-1040.42 | USN-4750-1 |
| Ubuntu 20.04 LTS | linux-gcp | 5.4.0-1037.40 | USN-4750-1 |
| Ubuntu 20.04 LTS | linux-gke | 5.4.0-1036.38 | — |
| Ubuntu 20.04 LTS | linux-gkeop | 5.4.0-1010.11 | USN-4750-1 |
| Ubuntu 20.04 LTS | linux-hwe-5.8 | 5.8.0-44.50~20.04.1 | USN-4751-1 |
| Ubuntu 20.04 LTS | linux-kvm | 5.4.0-1033.34 | USN-4750-1 |
| Ubuntu 20.04 LTS | linux-oem-5.10 | 5.10.0-1011.12 | — |
| Ubuntu 20.04 LTS | linux-oracle | 5.4.0-1038.41 | USN-4750-1 |
| Ubuntu 20.04 LTS | linux-raspi | 5.4.0-1029.32 | USN-4750-1 |
| Ubuntu 20.04 LTS | linux-riscv +2 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-riscv-5.8 | 5.8.0-17.19~20.04.1 | — |
| Ubuntu 18.04 LTS | linux | 4.15.0-136.140 | USN-4749-1 |
| Ubuntu 18.04 LTS | linux-aws | 4.15.0-1094.101 | USN-4749-1 |
| Ubuntu 18.04 LTS | linux-aws-5.4 | 5.4.0-1038.40~18.04.1 | USN-4750-1 |
| Ubuntu 18.04 LTS | linux-azure-4.15 | 4.15.0-1108.120 | USN-4749-1 |
| Ubuntu 18.04 LTS | linux-azure-5.4 | 5.4.0-1040.42~18.04.1 | USN-4750-1 |
| Ubuntu 18.04 LTS | linux-dell300x | 4.15.0-1012.16 | USN-4749-1 |
| Ubuntu 18.04 LTS | linux-gcp +12 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-gcp-4.15 | 4.15.0-1093.106 | USN-4749-1 |
| Ubuntu 18.04 LTS | linux-gcp-5.4 | 5.4.0-1037.40~18.04.1 | USN-4750-1 |
| Ubuntu 18.04 LTS | linux-gke-5.4 | 5.4.0-1036.38~18.04.1 | USN-4750-1 |
| Ubuntu 18.04 LTS | linux-gkeop-5.4 | 5.4.0-1010.11~18.04.1 | USN-4750-1 |
| Ubuntu 18.04 LTS | linux-hwe-5.4 | 5.4.0-66.74~18.04.2 | USN-4750-1 |
| Ubuntu 18.04 LTS | linux-kvm | 4.15.0-1085.87 | USN-4749-1 |
| Ubuntu 18.04 LTS | linux-oracle | 4.15.0-1065.73 | USN-4749-1 |
| Ubuntu 18.04 LTS | linux-oracle-5.4 | 5.4.0-1038.41~18.04.1 | USN-4750-1 |
| Ubuntu 18.04 LTS | linux-raspi-5.4 | 5.4.0-1029.32~18.04.1 | USN-4750-1 |
| Ubuntu 18.04 LTS | linux-raspi2 +1 | 4.15.0-1079.84 | USN-4749-1 |
| Ubuntu 18.04 LTS | linux-snapdragon | 4.15.0-1096.105 | USN-4749-1 |
| Ubuntu 16.04 LTS | linux | 4.4.0-203.235 | USN-4748-1 |
| Ubuntu 16.04 LTS | linux-aws | 4.4.0-1122.136 | USN-4748-1 |
| Ubuntu 16.04 LTS | linux-aws-hwe | 4.15.0-1094.101~16.04.1 | USN-4749-1 |
| Ubuntu 16.04 LTS | linux-azure | 4.15.0-1108.120~16.04.1 | USN-4749-1 |
| Ubuntu 16.04 LTS | linux-gcp | 4.15.0-1093.106~16.04.1 | USN-4749-1 |
| Ubuntu 16.04 LTS | linux-hwe | 4.15.0-136.140~16.04.1 | USN-4749-1 |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
| Ubuntu 16.04 LTS | linux-kvm | 4.4.0-1088.97 | USN-4748-1 |
| Ubuntu 16.04 LTS | linux-oracle | 4.15.0-1065.73~16.04.1 | USN-4749-1 |
| Ubuntu 16.04 LTS | linux-raspi2 | 4.4.0-1146.156 | USN-4748-1 |
| Ubuntu 16.04 LTS | linux-snapdragon | 4.4.0-1150.160 | USN-4748-1 |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro FIPS 20.04 LTS | linux-aws-fips +2 | No fix yet | — |
| Ubuntu Pro FIPS 18.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS 16.04 LTS | linux-fips | No fix yet | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-aws-fips | 5.4.0-1069.73+fips2 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-azure-fips | 5.4.0-1073.76+fips1 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-gcp-fips | 5.4.0-1067.71~20.04.1 | — |
| Ubuntu Pro FIPS-updates 18.04 LTS | linux-aws-fips | 4.15.0-2037.39 | — |
| Ubuntu Pro FIPS-updates 18.04 LTS | linux-azure-fips | 4.15.0-2020.23 | — |
| Ubuntu Pro FIPS-updates 18.04 LTS | linux-fips | 4.15.0-1053.61 | — |
| Ubuntu Pro FIPS-updates 16.04 LTS | linux-fips | 4.4.0-1056.62 | — |
| Ubuntu Pro 20.04 LTS | linux-azure-fde-5.15 | 5.15.0-1114.123~20.04.1 | — |
| Ubuntu Pro 14.04 LTS | linux | No fix yet | — |
| Ubuntu Pro 14.04 LTS | linux-aws | 4.4.0-1086.90 | USN-4748-1 |
| Ubuntu Pro 14.04 LTS | linux-azure | 4.15.0-1108.120~14.04.1 | USN-4749-1 |
| Ubuntu Pro 14.04 LTS | linux-lts-xenial | 4.4.0-203.235~14.04.1 | USN-4748-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP2 | kernel-azure +2 | 5.3.18-18.35.2 | SUSE-SU-2021:0347-1 |
| SLES 15 SP2 | kernel-default-base | 5.3.18-24.49.2.9.21.2 | SUSE-SU-2021:0354-1 |
| SLES 15 SP2 | kernel-docs | 5.3.18-24.49.3 | SUSE-SU-2021:0354-1 |
| SLES 15 SP2 | kernel-syms +4 | 5.3.18-24.49.2 | SUSE-SU-2021:0354-1 |
| SLES 15 SP1 | kernel-docs +5 | 4.12.14-197.83.1 | SUSE-SU-2021:0532-1 |
| SLES 15 | kernel-docs +6 | 4.12.14-150.66.1 | SUSE-SU-2021:0438-1 |
| SLES 12 SP5 | kernel-azure +2 | 4.12.14-16.44.1 | SUSE-SU-2021:0348-1 |
| SLES 12 SP5 | kernel-docs | 4.12.14-122.60.2 | SUSE-SU-2021:0353-1 |
| SLES 12 SP5 | kernel-syms +3 | 4.12.14-122.60.1 | SUSE-SU-2021:0353-1 |
| SLES 12 SP4 | kernel-syms +2 | 4.12.14-95.68.1 | SUSE-SU-2021:0434-1 |
Show 28 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP3 | kernel-syms +2 | 4.4.180-94.138.1 | SUSE-SU-2021:0452-1 |
| SLES 12 SP3 | kgraft-patch-SLE12-SP3_Update_37 | 1-4.3.1 | SUSE-SU-2021:0452-1 |
| SLES 12 SP2 | kernel-syms +2 | 4.4.121-92.149.1 | SUSE-SU-2021:0437-1 |
| SLES 12 SP2 | kgraft-patch-SLE12-SP2_Update_39 | 1-3.3.1 | SUSE-SU-2021:0437-1 |
| SLES for SAP 15 SP1 | kernel-docs +4 | 4.12.14-197.83.1 | SUSE-SU-2021:0532-1 |
| SLES for SAP 15 | kernel-docs +5 | 4.12.14-150.66.1 | SUSE-SU-2021:0438-1 |
| SLES for SAP 12 SP5 | kernel-azure +2 | 4.12.14-16.44.1 | SUSE-SU-2021:0348-1 |
| SLES for SAP 12 SP5 | kernel-syms +2 | 4.12.14-122.60.1 | SUSE-SU-2021:0353-1 |
| SLES for SAP 12 SP4 | kernel-syms +2 | 4.12.14-95.68.1 | SUSE-SU-2021:0434-1 |
| SLES for SAP 12 SP3 | kernel-syms +2 | 4.4.180-94.138.1 | SUSE-SU-2021:0452-1 |
| SLES for SAP 12 SP3 | kgraft-patch-SLE12-SP3_Update_37 | 1-4.3.1 | SUSE-SU-2021:0452-1 |
| SLES for SAP 12 SP2 | kernel-syms +2 | 4.4.121-92.149.1 | SUSE-SU-2021:0437-1 |
| SLES for SAP 12 SP2 | kgraft-patch-SLE12-SP2_Update_39 | 1-3.3.1 | SUSE-SU-2021:0437-1 |
| SLE Real Time 12 SP5 | kernel-rt +3 | 4.12.14-10.31.1 | SUSE-SU-2021:0433-1 |
| SLE Live Patching 15 SP2 | kernel-default | 5.3.18-24.49.2 | SUSE-SU-2021:0354-1 |
| SLE Live Patching 15 SP2 | kernel-livepatch-SLE15-SP2_Update_10 | 1-5.3.2 | SUSE-SU-2021:0354-1 |
| SLE Live Patching 15 SP1 | kernel-default | 4.12.14-197.83.1 | SUSE-SU-2021:0532-1 |
| SLE Live Patching 15 SP1 | kernel-livepatch-SLE15-SP1_Update_22 | 1-3.5.1 | SUSE-SU-2021:0532-1 |
| SLE Live Patching 15 | kernel-default | 4.12.14-150.66.1 | SUSE-SU-2021:0438-1 |
| SLE Live Patching 15 | kernel-livepatch-SLE15_Update_22 | 1-1.3.1 | SUSE-SU-2021:0438-1 |
| SLE Live Patching 12 SP5 | kernel-default | 4.12.14-122.60.1 | SUSE-SU-2021:0353-1 |
| SLE Live Patching 12 SP5 | kgraft-patch-SLE12-SP5_Update_15 | 1-8.3.1 | SUSE-SU-2021:0353-1 |
| SLE Live Patching 12 SP4 | kernel-default | 4.12.14-95.68.1 | SUSE-SU-2021:0434-1 |
| SLE Live Patching 12 SP4 | kgraft-patch-SLE12-SP4_Update_18 | 1-6.3.1 | SUSE-SU-2021:0434-1 |
| SLE HPC 15 SP1 | kernel-docs +4 | 4.12.14-197.83.1 | SUSE-SU-2021:0532-1 |
| SLE HPC 15 | kernel-docs +5 | 4.12.14-150.66.1 | SUSE-SU-2021:0438-1 |
| SUSE Real Time Module 15 SP2 | kernel-rt +3 | 5.3.18-25.1 | SUSE-SU-2021:0427-1 |
| SUSE OpenStack Cloud Crowbar 9 | kernel-syms +2 | 4.12.14-95.68.1 | SUSE-SU-2021:0434-1 |
| SUSE OpenStack Cloud Crowbar 8 | kernel-syms +2 | 4.4.180-94.138.1 | SUSE-SU-2021:0452-1 |
| SUSE OpenStack Cloud Crowbar 8 | kgraft-patch-SLE12-SP3_Update_37 | 1-4.3.1 | SUSE-SU-2021:0452-1 |
| SUSE OpenStack Cloud 9 | kernel-syms +2 | 4.12.14-95.68.1 | SUSE-SU-2021:0434-1 |
| SUSE OpenStack Cloud 8 | kernel-syms +2 | 4.4.180-94.138.1 | SUSE-SU-2021:0452-1 |
| SUSE OpenStack Cloud 8 | kgraft-patch-SLE12-SP3_Update_37 | 1-4.3.1 | SUSE-SU-2021:0452-1 |
| SUSE OpenStack Cloud 7 | kernel-syms +2 | 4.4.121-92.149.1 | SUSE-SU-2021:0437-1 |
| SUSE OpenStack Cloud 7 | kgraft-patch-SLE12-SP2_Update_39 | 1-3.3.1 | SUSE-SU-2021:0437-1 |
| SUSE Manager Server 4.0 | kernel-docs +5 | 4.12.14-197.83.1 | SUSE-SU-2021:0532-1 |
| SUSE Manager Retail Branch Server 4.0 | kernel-docs +4 | 4.12.14-197.83.1 | SUSE-SU-2021:0532-1 |
| SUSE Manager Proxy 4.0 | kernel-docs +4 | 4.12.14-197.83.1 | SUSE-SU-2021:0532-1 |
| SUSE HPE Helion OpenStack 8 | kernel-syms +2 | 4.4.180-94.138.1 | SUSE-SU-2021:0452-1 |
| SUSE HPE Helion OpenStack 8 | kgraft-patch-SLE12-SP3_Update_37 | 1-4.3.1 | SUSE-SU-2021:0452-1 |
| SUSE Enterprise Storage 6 | kernel-docs +4 | 4.12.14-197.83.1 | SUSE-SU-2021:0532-1 |
| SUSE Enterprise Storage 5 | kernel-syms +2 | 4.4.180-94.138.1 | SUSE-SU-2021:0452-1 |
| SUSE Enterprise Storage 5 | kgraft-patch-SLE12-SP3_Update_37 | 1-4.3.1 | SUSE-SU-2021:0452-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.2 | kernel-default-base | 5.3.18-lp152.63.1.lp152.8.21.1 | openSUSE-SU-2021:0241-1 |
| openSUSE Leap 15.2 | kernel-docs +8 | 5.3.18-lp152.63.1 | openSUSE-SU-2021:0241-1 |
| openSUSE Leap 15.1 | kernel-docs +8 | 4.12.14-lp151.28.91.1 | openSUSE-SU-2021:0075-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.23 | linux-lts | 5.10.4-r0 | — |
| Alpine v3.22 | linux-lts | 5.10.4-r0 | — |
| Alpine v3.21 | linux-lts | 5.10.4-r0 | — |
| Alpine v3.20 | linux-lts | 5.10.4-r0 | — |
| Alpine v3.19 | linux-lts | 5.10.4-r0 | — |
Show 6 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.18 | linux-lts | 5.10.4-r0 | — |
| Alpine v3.17 | linux-lts | 5.10.4-r0 | — |
| Alpine v3.16 | linux-lts | 5.10.4-r0 | — |
| Alpine v3.15 | linux-lts | 5.10.4-r0 | — |
| Alpine v3.14 | linux-lts | 5.10.4-r0 | — |
| Alpine v3.13 | linux-lts | 5.10.4-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | kernel-livepatch-4.14.214-160.339 | 1.0-0.amzn2 | ALAS2-2021-1588 |
| Amazon Linux 2 | perf +8 | 4.14.214-160.339.amzn2 | ALAS2-2021-1588 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | kernel-uek +5 | 4.1.12-124.46.4.1.el7uek | ELSA-2021-9037, ELSA-2021-9030, ELSA-2021-9023 |
| Oracle Linux 7 | kernel-uek-container | 4.14.35-2025.404.1.1.el7 | ELSA-2021-9038, ELSA-2021-9025, ELSA-2021-9024 |
| Oracle Linux 7 | kernel-uek-container-debug | 5.4.17-2036.102.0.2.el8 | ELSA-2021-9038, ELSA-2021-9007 |
| Oracle Linux 7 | perf +5 | 4.14.35-2025.404.1.1.el7uek | ELSA-2021-9037, ELSA-2021-9023, ELSA-2021-9006 |
Advisories 32
- USN-4748-1 linux, linux-aws, linux-kvm, linux-lts-xenial, linux-raspi2, linux-snapdragon vulnerabilities Ubuntu Security Notices (USN) · Jun 3, 2026
- USN-4750-1 linux, linux-aws, linux-aws-5.4, linux-azure, linux-azure-5.4, linux-gcp, linux-gcp-5.4, linux-gke-5.4, linux-gkeop, linux-gkeop-5.4, linux-hwe-5.4, linux-kvm, linux-oracle, linux-oracle-5.4, linux-raspi, linux-raspi-5.4 vulnerabilities Ubuntu Security Notices (USN) · Jun 3, 2026
- USN-4749-1 linux, linux-aws, linux-aws-hwe, linux-azure, linux-azure-4.15, linux-dell300x, linux-gcp, linux-gcp-4.15, linux-gke-4.15, linux-hwe, linux-kvm, linux-oracle, linux-raspi2, linux-snapdragon vulnerabilities Ubuntu Security Notices (USN) · Jun 3, 2026
- USN-4751-1 linux, linux-aws, linux-azure, linux-gcp, linux-hwe-5.8, linux-kvm, linux-oracle, linux-raspi vulnerabilities Ubuntu Security Notices (USN) · Jun 3, 2026
- DSA-4843-1 linux - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2557-1 linux-4.19 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2586-1 linux - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2021:0354-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0532-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0434-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0348-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0427-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0347-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0075-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0437-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0241-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0438-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0353-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0452-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · May 2, 2025
- SUSE-SU-2021:0433-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · May 2, 2025
- ELSA-2021-9037 Important: Unbreakable Enterprise kernel security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Feb 8, 2021
- ELSA-2021-9038 Important: Unbreakable Enterprise kernel-container security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Feb 8, 2021
- ELSA-2021-9030 Important: Unbreakable Enterprise kernel security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Feb 3, 2021
- ELSA-2021-9024 Important: Unbreakable Enterprise kernel-container security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Feb 1, 2021
- ELSA-2021-9025 Important: Unbreakable Enterprise kernel-container security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Feb 1, 2021
- ELSA-2021-9023 Important: Unbreakable Enterprise kernel security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jan 30, 2021
- ALAS2-2021-1588 Important: kernel security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Jan 26, 2021
- ELSA-2021-9007 Important: Unbreakable Enterprise kernel-container security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jan 12, 2021
- ELSA-2021-9005 Important: Unbreakable Enterprise kernel security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jan 12, 2021
- ELSA-2021-9009 Important: Unbreakable Enterprise kernel security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jan 12, 2021
- ELSA-2021-9008 Important: Unbreakable Enterprise kernel-container security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jan 12, 2021
- ELSA-2021-9006 Important: Unbreakable Enterprise kernel security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jan 12, 2021
References
- https://xenbits.xenproject.org/xsa/advisory-349.html
- DSA-4843 vendor-advisory
- [debian-lts-announce] 20210212 [SECURITY] [DLA 2557-1] linux-4.19 security update mailing-list
- [debian-lts-announce] 20210309 [SECURITY] [DLA 2586-1] linux security update mailing-list
- GLSA-202107-30 vendor-advisory