CVE-2026-23121: linux Race Condition

CVSS: 5.5v3.1MediumModified

AliasesUBUNTU-CVE-2026-23121DEBIAN-CVE-2026-23121

Published 14-02-2026Last modified 19-10-2026

Vulnerability summary

CVE-2026-23121 is a medium (CVSS 5.5) Race Condition vulnerability in linux. EPSS estimates a 0.14% chance of exploitation in the next 30 days, higher than 2.9% of scored vulnerabilities.

Overall risk

22/100

0100

Low · default modelHow is this calculated?

CVSS score

5.5/10

010

Medium · v3.1 (NVD)

EPSS score

0.14%

0%100%

Low · +0.02 pp in 30 days

KEVNot listedIn no KEV catalog

RansomwareNone recordedNo known use recorded

Public exploits0No public exploits recorded

Timeline

14-02-2026
PublishedVulnerability first disclosed.
19-10-2026
Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: mISDN: annotate data-race around dev->work dev->work can re read locklessly in mISDN_read() and mISDN_poll(). Add READ_ONCE()/WRITE_ONCE() annotations. BUG: KCSAN: data-race in mISDN_ioctl / mISDN_read write to 0xffff88812d848280 of 4 bytes by task 10864 on cpu 1: misdn_add_timer drivers/isdn/mISDN/timerdev.c:175 [inline] mISDN_ioctl+0x2fb/0x550 drivers/isdn/mISDN/timerdev.c:233 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xce/0x140 fs/ioctl.c:583 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583 x64_sys_call+0x14b0/0x3000 arch/x86/include/generated/asm/syscalls_64.h:17 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd8/0x2c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffff88812d848280 of 4 bytes by task 10857 on cpu 0: mISDN_read+0x1f2/0x470 drivers/isdn/mISDN/timerdev.c:112 do_loop_readv_writev fs/read_write.c:847 [inline] vfs_readv+0x3fb/0x690 fs/read_write.c:1020 do_readv+0xe7/0x210 fs/read_write.c:1080 __do_sys_readv fs/read_write.c:1165 [inline] __se_sys_readv fs/read_write.c:1162 [inline] __x64_sys_readv+0x45/0x50 fs/read_write.c:1162 x64_sys_call+0x2831/0x3000 arch/x86/include/generated/asm/syscalls_64.h:20 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd8/0x2c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0x00000000 -> 0x00000001

CVSS metrics

3 scores · 3 sources · 1 version

v3.15.5

EPSS trend

Probability

0.14%

Chance of exploitation in the next 30 days

Percentile

Versus all other CVEs

30-day change

+0.02 pp

From 0.12% on 19-09-2026

19-09-202619-10-2026

EPSS score

0.14%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

Affected systems

Ubuntu156 products

linuxAll versions (No fix recorded) | < 5.15.0-176.186 | < 6.8.0-117.117
linux-allwinner-5.19All versions (No fix recorded)
linux-awsAll versions (No fix recorded) | < 5.15.0-1105.112 | < 6.8.0-1055.58
linux-aws-5.0All versions (No fix recorded)
linux-aws-5.11All versions (No fix recorded)

linux-aws-5.13All versions (No fix recorded)
linux-aws-5.15< 5.15.0-1105.112~20.04.1
linux-aws-5.19All versions (No fix recorded)
linux-aws-5.3All versions (No fix recorded)
linux-aws-5.4All versions (No fix recorded)
linux-aws-5.8All versions (No fix recorded)
linux-aws-6.14All versions (No fix recorded)
linux-aws-6.17All versions (No fix recorded)
linux-aws-6.2All versions (No fix recorded)
linux-aws-6.5All versions (No fix recorded)
linux-aws-6.8< 6.8.0-1057.60~22.04.1
linux-aws-fipsAll versions (No fix recorded) | < 5.15.0-1105.112+fips1 | < 6.8.0-1055.58+fips1
linux-aws-hweAll versions (No fix recorded)
linux-azureAll versions (No fix recorded) | < 5.15.0-1110.119 | < 6.8.0-1056.62
linux-azure-4.15All versions (No fix recorded)
linux-azure-5.11All versions (No fix recorded)
linux-azure-5.13All versions (No fix recorded)
linux-azure-5.15< 5.15.0-1110.119~20.04.1
linux-azure-5.19All versions (No fix recorded)
linux-azure-5.3All versions (No fix recorded)
linux-azure-5.4All versions (No fix recorded)
linux-azure-5.8All versions (No fix recorded)
linux-azure-6.11All versions (No fix recorded)
linux-azure-6.14All versions (No fix recorded)
linux-azure-6.17< 6.17.0-1021.21~24.04.1
linux-azure-6.2All versions (No fix recorded)
linux-azure-6.5All versions (No fix recorded)
linux-azure-6.8< 6.8.0-1059.65~22.04.1
linux-azure-edgeAll versions (No fix recorded)
linux-azure-fdeAll versions (No fix recorded) | < 5.15.0-1114.123 | < 6.8.0-1058.65
linux-azure-fde-5.19All versions (No fix recorded)
linux-azure-fde-6.14All versions (No fix recorded)
linux-azure-fde-6.2All versions (No fix recorded)
linux-azure-fde-6.8< 6.8.0-1058.65~22.04.1
linux-azure-fipsAll versions (No fix recorded) | < 5.15.0-1110.119+fips1 | < 6.8.0-1059.65+fips1
linux-azure-nvidiaAll versions (No fix recorded)
linux-azure-nvidia-6.14All versions (No fix recorded)
linux-bluefieldAll versions (No fix recorded) | < 5.15.0-1089.91 | < 6.8.0-1022.26
linux-fipsAll versions (No fix recorded) | < 5.15.0-176.186+fips1 | < 6.8.0-116.116+fips1
linux-gcpAll versions (No fix recorded) | < 5.15.0-1105.114 | < 6.8.0-1058.61
linux-gcp-4.15All versions (No fix recorded)
linux-gcp-5.11All versions (No fix recorded)
linux-gcp-5.13All versions (No fix recorded)
linux-gcp-5.15< 5.15.0-1106.115~20.04.1
linux-gcp-5.19All versions (No fix recorded)
linux-gcp-5.3All versions (No fix recorded)
linux-gcp-5.4All versions (No fix recorded)
linux-gcp-5.8All versions (No fix recorded)
linux-gcp-6.11All versions (No fix recorded)
linux-gcp-6.14All versions (No fix recorded)
linux-gcp-6.17< 6.17.0-1021.24~24.04.1
linux-gcp-6.2All versions (No fix recorded)
linux-gcp-6.5All versions (No fix recorded)
linux-gcp-6.8< 6.8.0-1060.63~22.04.1
linux-gcp-fipsAll versions (No fix recorded) | < 5.15.0-1105.114+fips1 | < 6.8.0-1058.61+fips1
linux-gkeAll versions (No fix recorded) | < 5.15.0-1101.107 | < 6.8.0-1054.60
linux-gke-4.15All versions (No fix recorded)
linux-gke-5.15All versions (No fix recorded)
linux-gke-5.4All versions (No fix recorded)
linux-gkeopAll versions (No fix recorded) | < 5.15.0-1088.96 | < 6.8.0-1041.44
linux-gkeop-5.15All versions (No fix recorded)
linux-gkeop-5.4All versions (No fix recorded)
linux-hweAll versions (No fix recorded)
linux-hwe-5.11All versions (No fix recorded)
linux-hwe-5.13All versions (No fix recorded)
linux-hwe-5.15< 5.15.0-176.186~20.04.1
linux-hwe-5.19All versions (No fix recorded)
linux-hwe-5.4All versions (No fix recorded)
linux-hwe-5.8All versions (No fix recorded)
linux-hwe-6.11All versions (No fix recorded)
linux-hwe-6.14All versions (No fix recorded)
linux-hwe-6.17< 6.17.0-41.41~24.04.1
linux-hwe-6.2All versions (No fix recorded)
linux-hwe-6.5All versions (No fix recorded)
linux-hwe-6.8< 6.8.0-124.124~22.04.1
linux-hwe-edgeAll versions (No fix recorded)
linux-ibmAll versions (No fix recorded) | < 5.15.0-1099.102 | < 6.8.0-1055.56
linux-ibm-5.15< 5.15.0-1099.102~20.04.1
linux-ibm-5.4All versions (No fix recorded)
linux-ibm-6.8< 6.8.0-1055.56~22.04.1
linux-intel-5.13All versions (No fix recorded)
linux-intel-iot-realtimeAll versions (No fix recorded) | < 5.15.0-1097.99
linux-intel-iotg< 5.15.0-1100.106
linux-intel-iotg-5.15< 5.15.0-1100.106~20.04.1
linux-iotAll versions (No fix recorded)
linux-kvmAll versions (No fix recorded) | < 5.15.0-1097.102
linux-lowlatency< 5.15.0-175.185 | < 6.8.0-117.117.1
linux-lowlatency-hwe-5.15< 5.15.0-175.185~20.04.1
linux-lowlatency-hwe-5.19All versions (No fix recorded)
linux-lowlatency-hwe-6.11All versions (No fix recorded)
linux-lowlatency-hwe-6.2All versions (No fix recorded)
linux-lowlatency-hwe-6.5All versions (No fix recorded)
linux-lowlatency-hwe-6.8< 6.8.0-117.117.1~22.04.1
linux-lts-xenialAll versions (No fix recorded)
linux-nvidia< 5.15.0-1100.101 | < 6.8.0-1054.57
linux-nvidia-6.11All versions (No fix recorded)
linux-nvidia-6.17< 6.17.0-1031.31
linux-nvidia-6.2All versions (No fix recorded)
linux-nvidia-6.5All versions (No fix recorded)
linux-nvidia-6.8< 6.8.0-1054.57~22.04.1
linux-nvidia-lowlatency< 6.8.0-1054.57.1
linux-nvidia-tegra< 5.15.0-1057.57 | < 6.8.0-1024.24
linux-nvidia-tegra-5.15< 5.15.0-1057.57~20.04.1
linux-nvidia-tegra-igx< 5.15.0-1046.46
linux-oemAll versions (No fix recorded)
linux-oem-5.10All versions (No fix recorded)
linux-oem-5.13All versions (No fix recorded)
linux-oem-5.14All versions (No fix recorded)
linux-oem-5.17All versions (No fix recorded)
linux-oem-5.6All versions (No fix recorded)
linux-oem-6.0All versions (No fix recorded)
linux-oem-6.1All versions (No fix recorded)
linux-oem-6.11All versions (No fix recorded)
linux-oem-6.14All versions (No fix recorded)
linux-oem-6.17< 6.17.0-1030.30
linux-oem-6.5All versions (No fix recorded)
linux-oem-6.8All versions (No fix recorded)
linux-oracleAll versions (No fix recorded) | < 5.15.0-1102.108 | < 6.8.0-1054.55
linux-oracle-5.0All versions (No fix recorded)
linux-oracle-5.11All versions (No fix recorded)
linux-oracle-5.13All versions (No fix recorded)
linux-oracle-5.15< 5.15.0-1102.108~20.04.1
linux-oracle-5.3All versions (No fix recorded)
linux-oracle-5.4All versions (No fix recorded)
linux-oracle-5.8All versions (No fix recorded)
linux-oracle-6.14All versions (No fix recorded)
linux-oracle-6.17< 6.17.0-1019.19~24.04.3
linux-oracle-6.5All versions (No fix recorded)
linux-oracle-6.8< 6.8.0-1054.55~22.04.1
linux-raspiAll versions (No fix recorded) | < 5.15.0-1099.102 | < 6.8.0-1056.60
linux-raspi-5.4All versions (No fix recorded)
linux-raspi-realtimeAll versions (No fix recorded) | < 6.8.0-2045.46
linux-raspi2All versions (No fix recorded)
linux-realtimeAll versions (No fix recorded) | < 5.15.0-1104.113 | < 6.8.1-1051.52
linux-realtime-6.14All versions (No fix recorded)
linux-realtime-6.17< 6.17.0-1018.20~24.04.1
linux-realtime-6.8< 6.8.1-1051.52~22.04.1
linux-riscvAll versions (No fix recorded)
linux-riscv-5.11All versions (No fix recorded)
linux-riscv-5.15< 5.15.0-1099.103~20.04.1
linux-riscv-5.19All versions (No fix recorded)
linux-riscv-5.8All versions (No fix recorded)
linux-riscv-6.14All versions (No fix recorded)
linux-riscv-6.17All versions (No fix recorded)
linux-riscv-6.5All versions (No fix recorded)
linux-riscv-6.8< 6.8.0-117.117~22.04.1
linux-starfive-5.19All versions (No fix recorded)
linux-starfive-6.2All versions (No fix recorded)
linux-starfive-6.5All versions (No fix recorded)
linux-xilinx< 6.8.0-1032.33
linux-xilinx-zynqmpAll versions (No fix recorded) | < 5.15.0-1070.74

Show all 156

Linux2 products

linux≥ 1b2b03f8e514e4f68e293846ba511a948b80243c, < d5d99cb9e0839093cd53aa3b28176fce2f820ca0 | ≥ 1b2b03f8e514e4f68e293846ba511a948b80243c, < 13f3b3b87068898056db4c79ee67052fbde11d43 | ≥ 1b2b03f8e514e4f68e293846ba511a948b80243c, < accc3f8266d2a49881dbcf78c459477f4efa0ff3 | ≥ 1b2b03f8e514e4f68e293846ba511a948b80243c, < fc8ba17fd3337bd8b1913c30b95df0fee00d8fb7 | ≥ 1b2b03f8e514e4f68e293846ba511a948b80243c, < aa6e33cd74ca4965f2bbcb025e0b672fb0168a69 | ≥ 1b2b03f8e514e4f68e293846ba511a948b80243c, < 7ac345a93af31358e18e9606eb7b354691bf6757 | ≥ 1b2b03f8e514e4f68e293846ba511a948b80243c, < 8175dbf174d487afab81e936a862a8d9b8a1ccb6 | 2.6.27
linux_kernel≥ 2.6.27, < 5.10.249 | ≥ 5.11, < 5.15.199 | ≥ 5.16, < 6.1.162 | ≥ 6.2, < 6.6.122 | ≥ 6.7, < 6.12.68 | ≥ 6.13, < 6.18.8 | 6.19:rc1 | 6.19:rc2 | 6.19:rc3 | 6.19:rc4 | 6.19:rc5 | 6.19:rc6

Debian1 product

linux< 6.1.162-1 | < 6.12.69-1 | < 6.18.8-1

3 vendors · 159 products

References

40 links

git.kernel.org/stable/c/d5d99cb9e0839093cd53aa3b28176fce2f820ca0REPORTPatch
git.kernel.org/stable/c/13f3b3b87068898056db4c79ee67052fbde11d43REPORTPatch
git.kernel.org/stable/c/accc3f8266d2a49881dbcf78c459477f4efa0ff3REPORTPatch
git.kernel.org/stable/c/fc8ba17fd3337bd8b1913c30b95df0fee00d8fb7REPORTPatch
git.kernel.org/stable/c/aa6e33cd74ca4965f2bbcb025e0b672fb0168a69REPORTPatch
git.kernel.org/stable/c/7ac345a93af31358e18e9606eb7b354691bf6757REPORTPatch
git.kernel.org/stable/c/8175dbf174d487afab81e936a862a8d9b8a1ccb6REPORTPatch
ubuntu.com/security/CVE-2026-23121REPORT
www.cve.org/CVERecord?id=CVE-2026-23121REPORT
git.kernel.org/linus/8175dbf174d487afab81e936a862a8d9b8a1ccb6REPORT

Show all 40 references

ubuntu.com/security/notices/USN-8162-1Advisory
ubuntu.com/security/notices/USN-8180-1Advisory
ubuntu.com/security/notices/USN-8180-2Advisory
ubuntu.com/security/notices/USN-8186-1Advisory
ubuntu.com/security/notices/USN-8187-1Advisory
ubuntu.com/security/notices/USN-8188-1Advisory
ubuntu.com/security/notices/USN-8180-3Advisory
ubuntu.com/security/notices/USN-8180-4Advisory
ubuntu.com/security/notices/USN-8180-5Advisory
ubuntu.com/security/notices/USN-8243-1Advisory
ubuntu.com/security/notices/USN-8180-6Advisory
ubuntu.com/security/notices/USN-8275-1Advisory
ubuntu.com/security/notices/USN-8278-1Advisory
ubuntu.com/security/notices/USN-8289-1Advisory
ubuntu.com/security/notices/USN-8296-1Advisory
ubuntu.com/security/notices/USN-8297-1Advisory
ubuntu.com/security/notices/USN-8296-2Advisory
ubuntu.com/security/notices/USN-8289-2Advisory
ubuntu.com/security/notices/USN-8278-2Advisory
ubuntu.com/security/notices/USN-8393-1Advisory
ubuntu.com/security/notices/USN-8440-1Advisory
ubuntu.com/security/notices/USN-8499-1Advisory
ubuntu.com/security/notices/USN-8570-1Advisory
ubuntu.com/security/notices/USN-8594-1Advisory
ubuntu.com/security/notices/USN-8604-1Advisory
ubuntu.com/security/notices/USN-8605-1Advisory
ubuntu.com/security/notices/USN-8570-2Advisory
ubuntu.com/security/notices/USN-8669-1Advisory
security-tracker.debian.org/tracker/CVE-2026-23121Advisory
nvd.nist.gov/vuln/detail/CVE-2026-23121OvalAdvisory

Vulnerability summary

Advisory lineage

Timeline

Description

CVSS metrics

EPSS trend

Known exploited

Public exploits

Weaknesses

Affected systems

References

Related vulnerabilities