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CVE-2021-30178

An issue was discovered in the Linux kernel through 5.11.11. synic_get in arch/x86/kvm/hyperv.c...

5.5 MediumFix available

An issue was discovered in the Linux kernel through 5.11.11. synic_get in arch/x86/kvm/hyperv.c has a NULL pointer dereference for certain accesses to the SynIC Hyper-V context, aka CID-919f4ebc5987.

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

0.31%Down 0.1 points since Apr 14, 2021
90%50%10%1%

What each source reports

NVD Score used 5.5

An issue was discovered in the Linux kernel through 5.11.11. synic_get in arch/x86/kvm/hyperv.c has a NULL pointer dereference for certain accesses to the SynIC Hyper-V context, aka CID-919f4ebc5987.

Record
CVE-2021-30178
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0
2.1 LowAV:L/AC:L/Au:N/C:N/I:N/A:P
Weakness
CWE-476
Updated
2026-11-02
CVE List No score

An issue was discovered in the Linux kernel through 5.11.11. synic_get in arch/x86/kvm/hyperv.c has a NULL pointer dereference for certain accesses to the SynIC Hyper-V context, aka CID-919f4ebc5987.

Record
CVE-2021-30178
Updated
2026-11-02
EUVDEUVD-2021-17114 No score

An issue was discovered in the Linux kernel through 5.11.11. synic_get in arch/x86/kvm/hyperv.c has a NULL pointer dereference for certain accesses to the SynIC Hyper-V context, aka CID-919f4ebc5987.

Record
EUVD-2021-17114
Updated
2026-11-03
GitHub AdvisoriesGHSA-5qhm-686w-6256 No score

An issue was discovered in the Linux kernel through 5.11.11. synic_get in arch/x86/kvm/hyperv.c...

An issue was discovered in the Linux kernel through 5.11.11. synic_get in arch/x86/kvm/hyperv.c has a NULL pointer dereference for certain accesses to the SynIC Hyper-V context, aka CID-919f4ebc5987.

Record
GHSA-5qhm-686w-6256
Weakness
CWE-476
Updated
2026-11-02
OSVAZL-6556 5.5

CVE-2021-30178 affecting package kernel for versions less than 5.10.78.1-1

An issue was discovered in the Linux kernel through 5.11.11. synic_get in arch/x86/kvm/hyperv.c has a NULL pointer dereference for certain accesses to the SynIC Hyper-V context, aka CID-919f4ebc5987.

Record
AZL-6556
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVBELL-CVE-2021-30178 5.5

CVE-2021-30178 does not affect BellSoft software

Record
BELL-CVE-2021-30178
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2021-30178 5.5

An issue was discovered in the Linux kernel through 5.11.11. synic_get in arch/x86/kvm/hyperv.c has a NULL pointer dereference for certain accesses to the SynIC Hyper-V context, aka CID-919f4ebc5987.

Record
UBUNTU-CVE-2021-30178
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVCLSA-2024-1720468480 No score

kernel: Fix of 101 CVEs

  • kvm: initialize all of the kvm_debugregs structure before sending it to userspace {CVE-2023-1513}
  • wifi: mac80211: fix MBSSID parsing use-after-free {CVE-2022-42719}
  • mac80211: always allocate struct ieee802_11_elems {CVE-2022-42719}
  • netfilter: nf_tables: initialize registers in nft_do_chain() {CVE-2022-1016}
  • xprtrdma: fix incorrect header size calculations {CVE-2022-0812}
  • net: usb: fix memory leak in smsc75xx_bind {CVE-2021-47171}
  • i2c: i801: Don't generate an interrupt on bus reset {CVE-2021-47153}
  • pid: take a reference when initializing cad_pid {CVE-2021-47118}
  • Input: appletouch - initialize work before device registration {CVE-2021-46932}
  • HID: usbhid: fix info leak in hid_submit_ctrl {CVE-2021-46906}
  • quota: check block number when reading the block in quota file {CVE-2021-45868}
  • mwifiex: Fix skb_over_panic in mwifiex_usb_recv() {CVE-2021-43976}
  • atlantic: Fix OOB read and write in hw_atl_utils_fw_rpc_wait {CVE-2021-43975}
  • isdn: cpai: check ctr->cnr to avoid array index out of bound {CVE-2021-43389}
  • usb: hso: fix error handling code of hso_create_net_device {CVE-2021-37159}
  • can: bcm: fix infoleak in struct bcm_msg_head {CVE-2021-34693}
  • dm ioctl: fix out of bounds array access when no devices {CVE-2021-31916}
  • KVM: x86: hyper-v: Fix Hyper-V context null-ptr-deref {CVE-2021-30178}
  • perf/x86/intel: Fix a crash caused by zero PEBS status {CVE-2021-28971}
  • btrfs: fix race when cloning extent buffer during rewind of an old root {CVE-2021-28964}
  • ovl: fix missing negative dentry check in ovl_rename() {CVE-2021-20321}
  • drm/ttm/nouveau: don't call tt destroy callback on alloc failure. {CVE-2021-20292}
  • bpf: Verifer, adjust_scalar_min_max_vals to always call update_reg_bounds() {CVE-2021-4159}
  • btrfs: unlock newly allocated extent buffer after error {CVE-2021-4149}
  • tracing: Fix bug in rb_per_cpu_empty() that might cause deadloop. {CVE-2021-3679}
  • net: mac802154: Fix general protection fault {CVE-2021-3659}
  • nfsd4: readdirplus shouldn't return parent of export {CVE-2021-3178}
  • Bluetooth: SMP: Fail if remote and local public keys are identical {CVE-2021-0129}
  • drm/nouveau: clean up all clients on device removal {CVE-2020-27820}
  • drm/nouveau: Add a dedicated mutex for the clients list {CVE-2020-27820}
  • drm/nouveau: use drm_dev_unplug() during device removal {CVE-2020-27820}
  • Bluetooth: SMP: Fail if remote and local public keys are identical {CVE-2020-26555}
  • vsock: Fix memory leak in vsock_connect() {CVE-2022-3629}
  • RDMA/core: Don't infoleak GRH fields {CVE-2021-3923}
  • xen/netfront: force data bouncing when backend is untrusted {CVE-2022-33741}
  • net: Rename and export copy_skb_header
  • floppy: use a statically allocated error counter {CVE-2022-1652}
  • fuse: fix pipe buffer lifetime for direct_io {CVE-2022-1011}
  • aoe: fix the potential use-after-free problem in aoecmd_cfg_pkts {CVE-2024-26898}
  • smb: client: fix use-after-free bug in cifs_debug_data_proc_show() {CVE-2023-52752}
  • media: pvrusb2: fix use after free on context disconnection {CVE-2023-52445}
  • media: dm1105: Fix use after free bug in dm1105_remove due to race condition {CVE-2023-35824}
  • perf: Fix perf_event_validate_size() lockdep splat {CVE-2023-6931}
  • perf: Fix perf_event_validate_size() {CVE-2023-6931}
  • net/sched: sch_hfsc: Ensure inner classes have fsc curve {CVE-2023-4623}
  • relayfs: fix out-of-bounds access in relay_file_read {CVE-2023-3268}
  • xfs: verify buffer contents when we skip log replay {CVE-2023-2124}
  • Bluetooth: btsdio: fix use after free bug in btsdio_remove due to race condition {CVE-2023-1989}
  • Fix double fget() in vhost_net_set_backend() {CVE-2023-1838}
  • net/sched: cls_tcindex: downgrade to imperfect hash {CVE-2023-1829}
  • xen/netfront: fix leaking data in shared pages {CVE-2022-33740}
  • can: ems_usb: ems_usb_start_xmit(): fix double dev_kfree_skb() in error path {CVE-2022-28390}
  • xen/blkfront: fix leaking data in shared pages {CVE-2022-26365}
  • mISDN: fix use-after-free bugs in l1oip timer…
Record
CLSA-2024-1720468480
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
kernel
Azure Linux:2
before 5.10.78.1-1
5.10.78.1-1
bpftool
TuxCare:CentOS:7
From an advisory covering 89 CVEs
before 3.10.0-1160.119.1.el7.tuxcare.els1
3.10.0-1160.119.1.el7.tuxcare.els1
kernel
TuxCare:CentOS:7
From an advisory covering 89 CVEs
before 3.10.0-1160.119.1.el7.tuxcare.els1
3.10.0-1160.119.1.el7.tuxcare.els1
kernel-debug
TuxCare:CentOS:7
From an advisory covering 89 CVEs
before 3.10.0-1160.119.1.el7.tuxcare.els1
3.10.0-1160.119.1.el7.tuxcare.els1
kernel-debug-devel
TuxCare:CentOS:7
From an advisory covering 89 CVEs
before 3.10.0-1160.119.1.el7.tuxcare.els1
3.10.0-1160.119.1.el7.tuxcare.els1
kernel-devel
TuxCare:CentOS:7
From an advisory covering 89 CVEs
before 3.10.0-1160.119.1.el7.tuxcare.els1
3.10.0-1160.119.1.el7.tuxcare.els1
kernel-headers
TuxCare:CentOS:7
From an advisory covering 89 CVEs
before 3.10.0-1160.119.1.el7.tuxcare.els1
3.10.0-1160.119.1.el7.tuxcare.els1
kernel-tools
TuxCare:CentOS:7
From an advisory covering 89 CVEs
before 3.10.0-1160.119.1.el7.tuxcare.els1
3.10.0-1160.119.1.el7.tuxcare.els1
kernel-tools-libs
TuxCare:CentOS:7
From an advisory covering 89 CVEs
before 3.10.0-1160.119.1.el7.tuxcare.els1
3.10.0-1160.119.1.el7.tuxcare.els1
kernel-tools-libs-devel
TuxCare:CentOS:7
From an advisory covering 89 CVEs
before 3.10.0-1160.119.1.el7.tuxcare.els1
3.10.0-1160.119.1.el7.tuxcare.els1
Show 19 moreShow less
Affected packages
PackageAffectedFixed
perf
TuxCare:CentOS:7
From an advisory covering 89 CVEs
before 3.10.0-1160.119.1.el7.tuxcare.els1
3.10.0-1160.119.1.el7.tuxcare.els1
python-perf
TuxCare:CentOS:7
From an advisory covering 89 CVEs
before 3.10.0-1160.119.1.el7.tuxcare.els1
3.10.0-1160.119.1.el7.tuxcare.els1
linux-hwe-edge
Ubuntu: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 less
4.10.0-19.21~16.04.14.10.0-20.22~16.04.14.10.0-21.23~16.04.14.10.0-22.24~16.04.14.10.0-24.28~16.04.14.10.0-26.30~16.04.14.11.0-13.19~16.04.14.11.0-14.20~16.04.14.13.0-16.19~16.04.34.13.0-17.20~16.04.14.13.0-19.22~16.04.14.13.0-21.24~16.04.14.13.0-25.29~16.04.24.15.0-13.14~16.04.14.15.0-15.16~16.04.14.15.0-20.21~16.04.14.15.0-22.24~16.04.14.15.0-23.25~16.04.1
None known
linux-aws-5.0
Ubuntu: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-5.3
Ubuntu: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 less
5.3.0-1030.32~18.04.15.3.0-1032.34~18.04.25.3.0-1033.355.3.0-1034.365.3.0-1035.37
None known
linux-azure
Ubuntu: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 less
4.15.0-1012.124.15.0-1013.134.15.0-1014.144.15.0-1018.184.15.0-1019.194.15.0-1021.214.15.0-1022.234.15.0-1023.244.15.0-1025.264.15.0-1028.294.15.0-1030.314.15.0-1031.324.15.0-1032.334.15.0-1035.364.15.0-1036.384.15.0-1037.394.18.0-1011.11~18.04.14.18.0-1013.13~18.04.14.18.0-1014.14~18.04.14.18.0-1018.18~18.04.14.18.0-1019.19~18.04.14.18.0-1020.20~18.04.14.18.0-1023.24~18.04.14.18.0-1024.25~18.04.14.18.0-1025.27~18.04.15.0.0-1014.14~18.04.15.0.0-1016.17~18.04.15.0.0-1018.19~18.04.15.0.0-1020.21~18.04.15.0.0-1022.23~18.04.15.0.0-1023.24~18.04.15.0.0-1025.27~18.04.15.0.0-1027.29~18.04.15.0.0-1028.30~18.04.15.0.0-1029.31~18.04.15.0.0-1031.335.0.0-1032.345.0.0-1035.375.0.0-1036.38
None known
linux-azure-5.3
Ubuntu: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 less
5.3.0-1013.14~18.04.15.3.0-1016.17~18.04.15.3.0-1018.19~18.04.15.3.0-1019.20~18.04.15.3.0-1020.21~18.04.15.3.0-1022.23~18.04.15.3.0-1028.29~18.04.15.3.0-1031.32~18.04.15.3.0-1032.33~18.04.15.3.0-1034.35~18.04.15.3.0-1035.36
None known
linux-azure-edge
Ubuntu: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
linux-gcp
Ubuntu: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 less
4.15.0-1009.94.15.0-1010.104.15.0-1014.144.15.0-1015.154.15.0-1017.184.15.0-1018.194.15.0-1019.204.15.0-1021.224.15.0-1023.244.15.0-1024.254.15.0-1025.264.15.0-1026.274.15.0-1027.284.15.0-1028.294.15.0-1029.314.15.0-1030.324.15.0-1032.344.15.0-1033.354.15.0-1034.364.15.0-1036.384.15.0-1037.394.15.0-1040.424.15.0-1042.454.15.0-1044.705.0.0-1020.20~18.04.15.0.0-1021.21~18.04.15.0.0-1025.26~18.04.15.0.0-1026.27~18.04.15.0.0-1028.29~18.04.15.0.0-1029.30~18.04.15.0.0-1031.325.0.0-1033.345.0.0-1034.35
None known
linux-gcp-5.3
Ubuntu: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 less
5.3.0-1016.17~18.04.15.3.0-1017.18~18.04.15.3.0-1018.19~18.04.15.3.0-1020.22~18.04.15.3.0-1026.28~18.04.15.3.0-1029.31~18.04.15.3.0-1030.32~18.04.15.3.0-1032.34~18.04.1
None known
linux-gcp-edge
Ubuntu: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 less
4.18.0-1009.10~18.04.14.18.0-1011.12~18.04.14.18.0-1012.13~18.04.14.18.0-1013.14~18.04.14.18.0-1015.16~18.04.15.0.0-1011.11~18.04.15.0.0-1013.13~18.04.1
None known
linux-gke-4.15
Ubuntu: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 less
4.15.0-1037.394.15.0-1040.424.15.0-1041.434.15.0-1042.444.15.0-1044.464.15.0-1045.484.15.0-1046.494.15.0-1048.514.15.0-1049.524.15.0-1050.534.15.0-1052.554.15.0-1055.584.15.0-1057.604.15.0-1058.614.15.0-1059.624.15.0-1063.664.15.0-1064.674.15.0-1066.694.15.0-1067.704.15.0-1069.724.15.0-1070.734.15.0-1072.764.15.0-1073.784.15.0-1074.794.15.0-1076.814.15.0-1077.824.15.0-1078.834.15.0-1079.84
None known
linux-hwe
Ubuntu: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 less
4.18.0-18.19~18.04.14.18.0-20.21~18.04.14.18.0-21.22~18.04.14.18.0-22.23~18.04.14.18.0-24.25~18.04.14.18.0-25.26~18.04.15.0.0-23.24~18.04.15.0.0-25.26~18.04.15.0.0-27.28~18.04.15.0.0-29.31~18.04.15.0.0-31.33~18.04.15.0.0-32.34~18.04.25.0.0-35.38~18.04.15.0.0-36.39~18.04.15.0.0-37.40~18.04.15.3.0-26.28~18.04.15.3.0-28.30~18.04.15.3.0-40.32~18.04.15.3.0-42.34~18.04.15.3.0-45.37~18.04.15.3.0-46.38~18.04.15.3.0-51.44~18.04.25.3.0-53.47~18.04.15.3.0-59.53~18.04.15.3.0-61.55~18.04.15.3.0-62.56~18.04.15.3.0-64.58~18.04.15.3.0-65.595.3.0-66.605.3.0-67.615.3.0-68.635.3.0-69.655.3.0-70.665.3.0-72.685.3.0-73.695.3.0-74.705.3.0-75.715.3.0-76.72
None known
linux-hwe-edge
Ubuntu: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 less
5.3.0-19.20~18.04.25.3.0-22.24~18.04.15.3.0-23.25~18.04.15.3.0-23.25~18.04.25.3.0-24.26~18.04.2
None known
linux-oem
Ubuntu: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 less
4.15.0-1012.154.15.0-1013.164.15.0-1015.184.15.0-1017.204.15.0-1018.214.15.0-1021.244.15.0-1024.294.15.0-1026.314.15.0-1028.334.15.0-1030.354.15.0-1033.384.15.0-1034.394.15.0-1035.404.15.0-1036.414.15.0-1038.434.15.0-1039.444.15.0-1043.484.15.0-1045.504.15.0-1050.574.15.0-1056.654.15.0-1057.664.15.0-1059.684.15.0-1063.724.15.0-1064.734.15.0-1065.754.15.0-1066.764.15.0-1067.774.15.0-1069.794.15.0-1073.834.15.0-1076.864.15.0-1079.894.15.0-1080.904.15.0-1081.914.15.0-1087.974.15.0-1090.1004.15.0-1091.1014.15.0-1093.1034.15.0-1094.1044.15.0-1096.1064.15.0-1097.1074.15.0-1099.1094.15.0-1100.1104.15.0-1101.1124.15.0-1102.1134.15.0-1103.114
None known
linux-oracle-5.0
Ubuntu: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-5.3
Ubuntu: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 less
5.3.0-1024.26~18.04.15.3.0-1027.29~18.04.15.3.0-1028.30~18.04.15.3.0-1030.32~18.04.1
None known
linux-raspi2
Ubuntu: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-riscv
Ubuntu: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
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5.4.0-31.355.4.0-33.375.4.0-34.385.4.0-36.415.4.0-37.425.4.0-39.445.4.0-40.45
None known

History

History
RecordedChangedSources
affected, facts
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-30178 is a medium vulnerability (CVSS 5.5) in Linux Kernel, published April 6, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.31%, the 23rd percentile. Fixed in kernel 5.10.78.1-1.

References

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This page doesn't list everything

Left out here: the rest of 1 source description. The JSON record has them.

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