CVE-2021-38203
btrfs in the Linux kernel before 5.13.4 allows attackers to cause a denial of service (deadlock)...
btrfs in the Linux kernel before 5.13.4 allows attackers to cause a denial of service (deadlock) via processes that trigger allocation of new system chunks during times when there is a shortage of free space in the system space_info.
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
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
5.5
btrfs in the Linux kernel before 5.13.4 allows attackers to cause a denial of service (deadlock) via processes that trigger allocation of new system chunks during times when there is a shortage of free space in the system space_info.
- Record
CVE-2021-38203- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 2.1 Low
AV:L/AC:L/Au:N/C:N/I:N/A:P - Weakness
- CWE-667
- Updated
- 2026-11-02
CVE List No score
btrfs in the Linux kernel before 5.13.4 allows attackers to cause a denial of service (deadlock) via processes that trigger allocation of new system chunks during times when there is a shortage of free space in the system space_info.
- Record
CVE-2021-38203- Updated
- 2026-11-02
EUVDEUVD-2021-24661 No score
btrfs in the Linux kernel before 5.13.4 allows attackers to cause a denial of service (deadlock) via processes that trigger allocation of new system chunks during times when there is a shortage of free space in the system space_info.
- Record
EUVD-2021-24661- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-5fjr-c5p8-hxvj
5.5
btrfs in the Linux kernel before 5.13.4 allows attackers to cause a denial of service (deadlock)...
btrfs in the Linux kernel before 5.13.4 allows attackers to cause a denial of service (deadlock) via processes that trigger allocation of new system chunks during times when there is a shortage of free space in the system space_info.
- Record
GHSA-5fjr-c5p8-hxvj- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-667, CWE-770
- Updated
- 2026-11-02
OSVAZL-6587
5.5
CVE-2021-38203 affecting package kernel for versions less than 5.10.78.1-1
btrfs in the Linux kernel before 5.13.4 allows attackers to cause a denial of service (deadlock) via processes that trigger allocation of new system chunks during times when there is a shortage of free space in the system space_info.
- Record
AZL-6587- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSV
5.5
btrfs in the Linux kernel before 5.13.4 allows attackers to cause a denial of service (deadlock) via processes that trigger allocation of new system chunks during times when there is a shortage of free space in the system space_info.
- Record
CVE-2021-38203- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVDEBIAN-CVE-2021-38203
5.5
btrfs in the Linux kernel before 5.13.4 allows attackers to cause a denial of service (deadlock) via processes that trigger allocation of new system chunks during times when there is a shortage of free space in the system space_info.
- Record
DEBIAN-CVE-2021-38203- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2021-38203
5.5
btrfs in the Linux kernel before 5.13.4 allows attackers to cause a denial of service (deadlock) via processes that trigger allocation of new system chunks during times when there is a shortage of free space in the system space_info.
- Record
UBUNTU-CVE-2021-38203- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVUSN-5096-1 No score
linux-oem-5.13 vulnerabilities
Valentina Palmiotti discovered that the io_uring subsystem in the Linux kernel could be coerced to free adjacent memory. A local attacker could use this to execute arbitrary code. (CVE-2021-41073)
Benedict Schlueter discovered that the BPF subsystem in the Linux kernel did not properly protect against Speculative Store Bypass (SSB) side- channel attacks in some situations. A local attacker could possibly use this to expose sensitive information. (CVE-2021-34556)
Piotr Krysiuk discovered that the BPF subsystem in the Linux kernel did not properly protect against Speculative Store Bypass (SSB) side-channel attacks in some situations. A local attacker could possibly use this to expose sensitive information. (CVE-2021-35477)
Murray McAllister discovered that the joystick device interface in the Linux kernel did not properly validate data passed via an ioctl(). A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code on systems with a joystick device registered. (CVE-2021-3612)
It was discovered that the tracing subsystem in the Linux kernel did not properly keep track of per-cpu ring buffer state. A privileged attacker could use this to cause a denial of service. (CVE-2021-3679)
It was discovered that the Option USB High Speed Mobile device driver in the Linux kernel did not properly handle error conditions. A physically proximate attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-37159)
Alois Wohlschlager discovered that the overlay file system in the Linux kernel did not restrict private clones in some situations. An attacker could use this to expose sensitive information. (CVE-2021-3732)
It was discovered that the Virtio console implementation in the Linux kernel did not properly validate input lengths in some situations. A local attacker could possibly use this to cause a denial of service (system crash). (CVE-2021-38160)
It was discovered that the BPF subsystem in the Linux kernel contained an integer overflow in its hash table implementation. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-38166)
Michael Wakabayashi discovered that the NFSv4 client implementation in the Linux kernel did not properly order connection setup operations. An attacker controlling a remote NFS server could use this to cause a denial of service on the client. (CVE-2021-38199)
It was discovered that the Sun RPC implementation in the Linux kernel contained an out-of-bounds access error. A remote attacker could possibly use this to cause a denial of service (system crash). (CVE-2021-38201)
It was discovered that the NFS server implementation in the Linux kernel contained an out-of-bounds read when the trace even framework is being used for nfsd. A remote attacker could possibly use this to cause a denial of service (system crash). (CVE-2021-38202)
Naohiro Aota discovered that the btrfs file system in the Linux kernel contained a race condition in situations that triggered allocations of new system chunks. A local attacker could possibly use this to cause a denial of service (deadlock). (CVE-2021-38203)
It was discovered that the MAX-3421 host USB device driver in the Linux kernel did not properly handle device removal events. A physically proximate attacker could use this to cause a denial of service (system crash). (CVE-2021-38204)
It was discovered that the Xilinx 10/100 Ethernet Lite device driver in the Linux kernel could report pointer addresses in some situations. An attacker could use this information to ease the exploitation of another vulnerability. (CVE-2021-38205)
It was discovered that the ext4 file system in the Linux kernel contained a race condition when writing xattrs to an inode. A local attacker could use this to cause a denial of service or possibly gain administrative privileges. (CVE-2021-40490)
- Record
USN-5096-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
kernelAzure Linux:2 |
before 5.10.78.1-1 | 5.10.78.1-1 |
linuxDebian:12 |
before 5.14.6-1 | 5.14.6-1 |
linuxDebian:13 |
before 5.14.6-1 | 5.14.6-1 |
linuxDebian:14 |
before 5.14.6-1 | 5.14.6-1 |
linux-hwe-edgeUbuntu:16.04:LTS |
All versions, plus listed versions 4.8.0-28.30~16.04.14.8.0-30.32~16.04.14.8.0-32.34~16.04.14.8.0-34.36~16.04.14.10.0-14.16~16.04.1 Show 18 moreShow less4.10.0-19.21~16.04.14.10.0-20.22~16.04.14.10.0-21.23~16.04.14.10.0-22.24~16.04.14.10.0-24.28~16.04.14.10.0-26.30~16.04.14.11.0-13.19~16.04.14.11.0-14.20~16.04.14.13.0-16.19~16.04.34.13.0-17.20~16.04.14.13.0-19.22~16.04.14.13.0-21.24~16.04.14.13.0-25.29~16.04.24.15.0-13.14~16.04.14.15.0-15.16~16.04.14.15.0-20.21~16.04.14.15.0-22.24~16.04.14.15.0-23.25~16.04.1 |
None known |
linux-aws-5.0Ubuntu:18.04:LTS |
All versions, plus listed versions 5.0.0-1021.24~18.04.15.0.0-1022.25~18.04.15.0.0-1023.26~18.04.15.0.0-1024.27~18.04.15.0.0-1025.285.0.0-1027.30 |
None known |
linux-aws-5.3Ubuntu:18.04:LTS |
All versions, plus listed versions 5.3.0-1016.17~18.04.15.3.0-1017.18~18.04.15.3.0-1019.21~18.04.15.3.0-1023.25~18.04.15.3.0-1028.30~18.04.1 Show 5 moreShow less5.3.0-1030.32~18.04.15.3.0-1032.34~18.04.25.3.0-1033.355.3.0-1034.365.3.0-1035.37 |
None known |
linux-azureUbuntu:18.04:LTS |
All versions, plus listed versions 4.15.0-1002.24.15.0-1003.34.15.0-1004.44.15.0-1008.84.15.0-1009.9 Show 39 moreShow less4.15.0-1012.124.15.0-1013.134.15.0-1014.144.15.0-1018.184.15.0-1019.194.15.0-1021.214.15.0-1022.234.15.0-1023.244.15.0-1025.264.15.0-1028.294.15.0-1030.314.15.0-1031.324.15.0-1032.334.15.0-1035.364.15.0-1036.384.15.0-1037.394.18.0-1011.11~18.04.14.18.0-1013.13~18.04.14.18.0-1014.14~18.04.14.18.0-1018.18~18.04.14.18.0-1019.19~18.04.14.18.0-1020.20~18.04.14.18.0-1023.24~18.04.14.18.0-1024.25~18.04.14.18.0-1025.27~18.04.15.0.0-1014.14~18.04.15.0.0-1016.17~18.04.15.0.0-1018.19~18.04.15.0.0-1020.21~18.04.15.0.0-1022.23~18.04.15.0.0-1023.24~18.04.15.0.0-1025.27~18.04.15.0.0-1027.29~18.04.15.0.0-1028.30~18.04.15.0.0-1029.31~18.04.15.0.0-1031.335.0.0-1032.345.0.0-1035.375.0.0-1036.38 |
None known |
linux-azure-5.3Ubuntu:18.04:LTS |
All versions, plus listed versions 5.3.0-1007.8~18.04.15.3.0-1008.9~18.04.15.3.0-1009.10~18.04.15.3.0-1010.11~18.04.15.3.0-1012.13~18.04.1 Show 11 moreShow less5.3.0-1013.14~18.04.15.3.0-1016.17~18.04.15.3.0-1018.19~18.04.15.3.0-1019.20~18.04.15.3.0-1020.21~18.04.15.3.0-1022.23~18.04.15.3.0-1028.29~18.04.15.3.0-1031.32~18.04.15.3.0-1032.33~18.04.15.3.0-1034.35~18.04.15.3.0-1035.36 |
None known |
linux-azure-edgeUbuntu:18.04:LTS |
All versions, plus listed versions 4.18.0-1006.6~18.04.14.18.0-1007.7~18.04.14.18.0-1008.8~18.04.15.0.0-1012.12~18.04.2 |
None known |
Show 18 moreShow less
| Package | Affected | Fixed |
|---|---|---|
linux-gcpUbuntu:18.04:LTS |
All versions, plus listed versions 4.15.0-1001.14.15.0-1003.34.15.0-1005.54.15.0-1006.64.15.0-1008.8 Show 33 moreShow less4.15.0-1009.94.15.0-1010.104.15.0-1014.144.15.0-1015.154.15.0-1017.184.15.0-1018.194.15.0-1019.204.15.0-1021.224.15.0-1023.244.15.0-1024.254.15.0-1025.264.15.0-1026.274.15.0-1027.284.15.0-1028.294.15.0-1029.314.15.0-1030.324.15.0-1032.344.15.0-1033.354.15.0-1034.364.15.0-1036.384.15.0-1037.394.15.0-1040.424.15.0-1042.454.15.0-1044.705.0.0-1020.20~18.04.15.0.0-1021.21~18.04.15.0.0-1025.26~18.04.15.0.0-1026.27~18.04.15.0.0-1028.29~18.04.15.0.0-1029.30~18.04.15.0.0-1031.325.0.0-1033.345.0.0-1034.35 |
None known |
linux-gcp-5.3Ubuntu:18.04:LTS |
All versions, plus listed versions 5.3.0-1008.9~18.04.15.3.0-1009.10~18.04.15.3.0-1010.11~18.04.15.3.0-1012.13~18.04.15.3.0-1014.15~18.04.1 Show 8 moreShow less5.3.0-1016.17~18.04.15.3.0-1017.18~18.04.15.3.0-1018.19~18.04.15.3.0-1020.22~18.04.15.3.0-1026.28~18.04.15.3.0-1029.31~18.04.15.3.0-1030.32~18.04.15.3.0-1032.34~18.04.1 |
None known |
linux-gcp-edgeUbuntu:18.04:LTS |
All versions, plus listed versions 4.18.0-1004.5~18.04.14.18.0-1005.6~18.04.14.18.0-1006.7~18.04.14.18.0-1007.8~18.04.14.18.0-1008.9~18.04.1 Show 7 moreShow less4.18.0-1009.10~18.04.14.18.0-1011.12~18.04.14.18.0-1012.13~18.04.14.18.0-1013.14~18.04.14.18.0-1015.16~18.04.15.0.0-1011.11~18.04.15.0.0-1013.13~18.04.1 |
None known |
linux-gke-4.15Ubuntu:18.04:LTS |
All versions, plus listed versions 4.15.0-1030.324.15.0-1032.344.15.0-1033.354.15.0-1034.364.15.0-1036.38 Show 28 moreShow less4.15.0-1037.394.15.0-1040.424.15.0-1041.434.15.0-1042.444.15.0-1044.464.15.0-1045.484.15.0-1046.494.15.0-1048.514.15.0-1049.524.15.0-1050.534.15.0-1052.554.15.0-1055.584.15.0-1057.604.15.0-1058.614.15.0-1059.624.15.0-1063.664.15.0-1064.674.15.0-1066.694.15.0-1067.704.15.0-1069.724.15.0-1070.734.15.0-1072.764.15.0-1073.784.15.0-1074.794.15.0-1076.814.15.0-1077.824.15.0-1078.834.15.0-1079.84 |
None known |
linux-hweUbuntu:18.04:LTS |
All versions, plus listed versions 4.18.0-13.14~18.04.14.18.0-14.15~18.04.14.18.0-15.16~18.04.14.18.0-16.17~18.04.14.18.0-17.18~18.04.1 Show 38 moreShow less4.18.0-18.19~18.04.14.18.0-20.21~18.04.14.18.0-21.22~18.04.14.18.0-22.23~18.04.14.18.0-24.25~18.04.14.18.0-25.26~18.04.15.0.0-23.24~18.04.15.0.0-25.26~18.04.15.0.0-27.28~18.04.15.0.0-29.31~18.04.15.0.0-31.33~18.04.15.0.0-32.34~18.04.25.0.0-35.38~18.04.15.0.0-36.39~18.04.15.0.0-37.40~18.04.15.3.0-26.28~18.04.15.3.0-28.30~18.04.15.3.0-40.32~18.04.15.3.0-42.34~18.04.15.3.0-45.37~18.04.15.3.0-46.38~18.04.15.3.0-51.44~18.04.25.3.0-53.47~18.04.15.3.0-59.53~18.04.15.3.0-61.55~18.04.15.3.0-62.56~18.04.15.3.0-64.58~18.04.15.3.0-65.595.3.0-66.605.3.0-67.615.3.0-68.635.3.0-69.655.3.0-70.665.3.0-72.685.3.0-73.695.3.0-74.705.3.0-75.715.3.0-76.72 |
None known |
linux-hwe-edgeUbuntu:18.04:LTS |
All versions, plus listed versions 5.0.0-15.16~18.04.15.0.0-16.17~18.04.15.0.0-17.18~18.04.15.0.0-19.20~18.04.15.0.0-20.21~18.04.1 Show 5 moreShow less5.3.0-19.20~18.04.25.3.0-22.24~18.04.15.3.0-23.25~18.04.15.3.0-23.25~18.04.25.3.0-24.26~18.04.2 |
None known |
linux-oemUbuntu:18.04:LTS |
All versions, plus listed versions 4.15.0-1002.34.15.0-1004.54.15.0-1006.94.15.0-1008.114.15.0-1009.12 Show 45 moreShow less4.15.0-1012.154.15.0-1013.164.15.0-1015.184.15.0-1017.204.15.0-1018.214.15.0-1021.244.15.0-1024.294.15.0-1026.314.15.0-1028.334.15.0-1030.354.15.0-1033.384.15.0-1034.394.15.0-1035.404.15.0-1036.414.15.0-1038.434.15.0-1039.444.15.0-1043.484.15.0-1045.504.15.0-1050.574.15.0-1056.654.15.0-1057.664.15.0-1059.684.15.0-1063.724.15.0-1064.734.15.0-1065.754.15.0-1066.764.15.0-1067.774.15.0-1069.794.15.0-1073.834.15.0-1076.864.15.0-1079.894.15.0-1080.904.15.0-1081.914.15.0-1087.974.15.0-1090.1004.15.0-1091.1014.15.0-1093.1034.15.0-1094.1044.15.0-1096.1064.15.0-1097.1074.15.0-1099.1094.15.0-1100.1104.15.0-1101.1124.15.0-1102.1134.15.0-1103.114 |
None known |
linux-oracle-5.0Ubuntu:18.04:LTS |
All versions, plus listed versions 5.0.0-1007.12~18.04.15.0.0-1008.13~18.04.15.0.0-1009.14~18.04.15.0.0-1010.15~18.04.15.0.0-1011.165.0.0-1013.185.0.0-1014.19 |
None known |
linux-oracle-5.3Ubuntu:18.04:LTS |
All versions, plus listed versions 5.3.0-1011.12~18.04.15.3.0-1013.14~18.04.15.3.0-1014.15~18.04.15.3.0-1016.18~18.04.15.3.0-1018.20~18.04.1 Show 4 moreShow less5.3.0-1024.26~18.04.15.3.0-1027.29~18.04.15.3.0-1028.30~18.04.15.3.0-1030.32~18.04.1 |
None known |
linux-oem-5.13Ubuntu:20.04:LTS |
before 5.13.0-1014.18, plus listed versions 5.13.0-1009.105.13.0-1010.115.13.0-1012.16 |
5.13.0-1014.18 |
linux-aws-5.8Ubuntu:20.04:LTS |
All versions, plus listed versions 5.8.0-1035.37~20.04.15.8.0-1038.40~20.04.15.8.0-1041.43~20.04.15.8.0-1042.44~20.04.1 |
None known |
linux-gcp-5.8Ubuntu:20.04:LTS |
All versions, plus listed versions 5.8.0-1032.34~20.04.15.8.0-1035.37~20.04.15.8.0-1038.40~20.04.15.8.0-1039.41 |
None known |
linux-oem-5.6Ubuntu:20.04:LTS |
All versions, plus listed versions 5.6.0-1007.75.6.0-1008.85.6.0-1010.105.6.0-1011.115.6.0-1013.13 Show 24 moreShow less5.6.0-1017.175.6.0-1018.185.6.0-1020.205.6.0-1021.215.6.0-1023.235.6.0-1026.265.6.0-1027.275.6.0-1028.285.6.0-1031.325.6.0-1032.335.6.0-1033.355.6.0-1034.365.6.0-1035.375.6.0-1036.395.6.0-1039.435.6.0-1042.465.6.0-1047.515.6.0-1048.525.6.0-1050.545.6.0-1052.565.6.0-1053.575.6.0-1054.585.6.0-1055.595.6.0-1056.60 |
None known |
linux-oracle-5.8Ubuntu:20.04:LTS |
All versions, plus listed versions 5.8.0-1031.32~20.04.25.8.0-1033.34~20.04.15.8.0-1034.35~20.04.25.8.0-1037.38~20.04.15.8.0-1038.39~20.04.1 |
None known |
linux-raspi2Ubuntu:20.04:LTS |
All versions, plus listed versions 5.3.0-1007.85.3.0-1014.165.3.0-1015.175.3.0-1017.195.4.0-1004.45.4.0-1006.6 |
None known |
linux-riscvUbuntu:20.04:LTS |
All versions, plus listed versions 5.4.0-24.285.4.0-26.305.4.0-27.315.4.0-28.325.4.0-30.34 Show 7 moreShow less5.4.0-31.355.4.0-33.375.4.0-34.385.4.0-36.415.4.0-37.425.4.0-39.445.4.0-40.45 |
None known |
linux-riscv-5.8Ubuntu:20.04:LTS |
All versions, plus listed versions 5.8.0-14.16~20.04.15.8.0-14.16~20.04.35.8.0-16.18~20.04.15.8.0-17.19~20.04.15.8.0-18.20~20.04.1 Show 5 moreShow less5.8.0-20.22~20.04.15.8.0-22.24~20.04.15.8.0-25.27~20.04.15.8.0-26.28~20.04.15.8.0-29.31~20.04.1 |
None known |
linux-oem-5.13Ubuntu:20.04:LTS From an advisory covering 16 CVEs |
before 5.13.0-1014.18, plus listed versions 5.13.0-1009.105.13.0-1010.115.13.0-1012.16 |
5.13.0-1014.18 |
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-2021-38203 is a medium vulnerability (CVSS 5.5) in Linux Kernel, published August 8, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.36%, the 30th percentile. Fixed in kernel 5.10.78.1-1.
References
cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.13.4
github.com/torvalds/linux/commit/1cb3db1cf383a3c7dbda1aa0ce748b0958759947
security.netapp.com/advisory/ntap-20210902-0010
nvd.nist.gov/vuln/detail/CVE-2021-38203
github.com/advisories/GHSA-5fjr-c5p8-hxvj
security-tracker.debian.org/tracker/CVE-2021-38203
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ubuntu.com/security/CVE-2021-38203
ubuntu.com/security/notices/USN-5096-1
cve.org/CVERecord?id=CVE-2021-38203
ubuntu.com/security/CVE-2021-3612
ubuntu.com/security/CVE-2021-3679
ubuntu.com/security/CVE-2021-3732
ubuntu.com/security/CVE-2021-34556
ubuntu.com/security/CVE-2021-35477
ubuntu.com/security/CVE-2021-37159
ubuntu.com/security/CVE-2021-38160
ubuntu.com/security/CVE-2021-38166
ubuntu.com/security/CVE-2021-38199
ubuntu.com/security/CVE-2021-38201
ubuntu.com/security/CVE-2021-38202
ubuntu.com/security/CVE-2021-38204
ubuntu.com/security/CVE-2021-38205
ubuntu.com/security/CVE-2021-40490
ubuntu.com/security/CVE-2021-41073