Is CVE-2025-21856 in the CISA KEV catalog?

No. CVE-2025-21856 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2025-21856?

CVE-2025-21856 has a CVSS v3 base score of 7.8 (HIGH).

What is the EPSS score for CVE-2025-21856?

CVE-2025-21856 has an EPSS score of 0.21% (11th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2025-21856?

Upgrade linux on debian 13 to 6.12.17-1 or later. Fixes are available for 140 affected products.

CVE & CISA-KEV Catalog

CVE-2025-21856

HIGH

7.8

CVSS v3

NVD

Description

In the Linux kernel, the following vulnerability has been resolved: s390/ism: add release function for struct device According to device_release() in /drivers/base/core.c, a device without a release function is a broken device and must be fixed. The current code directly frees the device after calling device_add() without waiting for other kernel parts to release their references. Thus, a reference could still be held to a struct device, e.g., by sysfs, leading to potential use-after-free issues if a proper release function is not set.

CWE-416Use After Free

How to fix

Remediation Available

linuxDebian

Fixed in:6.12.17-1CVE-2025-21856

linuxUbuntu

Fixed in:6.8.0-78.78USN-7703-1

linux-awsUbuntu

Fixed in:6.8.0-1035.37USN-7703-1

linux-aws-6.8Ubuntu

Fixed in:6.8.0-1035.37~22.04.1USN-7703-2

linux-azureUbuntu

Fixed in:6.8.0-1034.39USN-7737-1

linux-azure-6.11Ubuntu

Fixed in:6.11.0-1015.15~24.04.1USN-7521-1

linux-azure-6.8Ubuntu

Fixed in:6.8.0-1034.39~22.04.1USN-7737-1

linux-azure-nvidiaUbuntu

Fixed in:6.8.0-1022.23USN-7737-1

linux-gcpUbuntu

Fixed in:6.8.0-1036.38USN-7703-2

linux-gcp-6.11Ubuntu

Fixed in:6.11.0-1015.15~24.04.1USN-7521-1

linux-gcp-6.8Ubuntu

Fixed in:6.8.0-1036.38~22.04.1USN-7703-2

linux-gkeUbuntu

Fixed in:6.8.0-1032.36USN-7703-4

linux-gkeopUbuntu

Fixed in:6.8.0-1019.21USN-7703-2

linux-hwe-6.11Ubuntu

Fixed in:6.11.0-26.26~24.04.1USN-7521-1

linux-hwe-6.8Ubuntu

Fixed in:6.8.0-78.78~22.04.1USN-7703-4

linux-ibmUbuntu

Fixed in:6.8.0-1033.33USN-7703-2

linux-ibm-6.8Ubuntu

Fixed in:6.8.0-1033.33~22.04.1USN-7703-2

linux-image-6.11.0-1014-lowlatencyUbuntu

Fixed in:6.11.0-1014.15~24.04.1USN-7521-3

linux-image-6.11.0-1014-lowlatency-64kUbuntu

Fixed in:6.11.0-1014.15~24.04.1USN-7521-3

linux-image-6.11.0-1015-azureUbuntu

Fixed in:6.11.0-1015.15~24.04.1USN-7521-1

linux-image-6.11.0-1015-azure-fdeUbuntu

Fixed in:6.11.0-1015.15~24.04.1USN-7521-1

linux-image-6.11.0-1015-gcpUbuntu

Fixed in:6.11.0-1015.15~24.04.1USN-7521-1

linux-image-6.11.0-1015-gcp-64kUbuntu

Fixed in:6.11.0-1015.15~24.04.1USN-7521-1

linux-image-6.11.0-1022-oemUbuntu

Fixed in:6.11.0-1022.22USN-7521-1

linux-image-6.11.0-26-genericUbuntu

Fixed in:6.11.0-26.26~24.04.1USN-7521-1

linux-image-6.11.0-26-generic-64kUbuntu

Fixed in:6.11.0-26.26~24.04.1USN-7521-1

linux-image-6.8.0-1019-gkeopUbuntu

Fixed in:6.8.0-1019.21USN-7703-2

linux-image-6.8.0-1022-azure-nvidiaUbuntu

Fixed in:6.8.0-1022.23USN-7737-1

linux-image-6.8.0-1032-gkeUbuntu

Fixed in:6.8.0-1032.36USN-7703-4

linux-image-6.8.0-1032-oracleUbuntu

Fixed in:6.8.0-1032.33~22.04.1USN-7703-3

Fixed in:6.8.0-1032.33USN-7703-3

linux-image-6.8.0-1032-oracle-64kUbuntu

Fixed in:6.8.0-1032.33~22.04.1USN-7703-3

Fixed in:6.8.0-1032.33USN-7703-3

linux-image-6.8.0-1033-ibmUbuntu

Fixed in:6.8.0-1033.33~22.04.1USN-7703-2

Fixed in:6.8.0-1033.33USN-7703-2

linux-image-6.8.0-1034-azureUbuntu

Fixed in:6.8.0-1034.39~22.04.1USN-7737-1

Fixed in:6.8.0-1034.39USN-7737-1

linux-image-6.8.0-1034-azure-fdeUbuntu

Fixed in:6.8.0-1034.39~22.04.1USN-7737-1

Fixed in:6.8.0-1034.39USN-7737-1

linux-image-6.8.0-1035-awsUbuntu

Fixed in:6.8.0-1035.37~22.04.1USN-7703-2

Fixed in:6.8.0-1035.37USN-7703-1

linux-image-6.8.0-1035-aws-64kUbuntu

Fixed in:6.8.0-1035.37~22.04.1USN-7703-2

Fixed in:6.8.0-1035.37USN-7703-1

linux-image-6.8.0-1035-nvidiaUbuntu

Fixed in:6.8.0-1035.38~22.04.1USN-7703-4

Fixed in:6.8.0-1035.38USN-7703-4

linux-image-6.8.0-1035-nvidia-64kUbuntu

Fixed in:6.8.0-1035.38~22.04.1USN-7703-4

Fixed in:6.8.0-1035.38USN-7703-4

linux-image-6.8.0-1035-nvidia-lowlatencyUbuntu

Fixed in:6.8.0-1035.38.1USN-7703-4

linux-image-6.8.0-1035-nvidia-lowlatency-64kUbuntu

Fixed in:6.8.0-1035.38.1USN-7703-4

linux-image-6.8.0-1035-raspiUbuntu

Fixed in:6.8.0-1035.39USN-7703-4

linux-image-6.8.0-1036-gcpUbuntu

Fixed in:6.8.0-1036.38~22.04.1USN-7703-2

Fixed in:6.8.0-1036.38USN-7703-2

linux-image-6.8.0-1036-gcp-64kUbuntu

Fixed in:6.8.0-1036.38~22.04.1USN-7703-2

Fixed in:6.8.0-1036.38USN-7703-2

linux-image-6.8.0-2028-raspi-realtimeUbuntu

Fixed in:6.8.0-2028.29USN-7719-1

linux-image-6.8.0-78-genericUbuntu

Fixed in:6.8.0-78.78~22.04.1USN-7703-4

Fixed in:6.8.0-78.78USN-7703-1

linux-image-6.8.0-78-generic-64kUbuntu

Fixed in:6.8.0-78.78~22.04.1USN-7703-4

Fixed in:6.8.0-78.78USN-7703-1

linux-image-6.8.0-78-lowlatencyUbuntu

Fixed in:6.8.0-78.78.1~22.04.1USN-7703-1

Fixed in:6.8.0-78.78.1USN-7703-1

linux-image-6.8.0-78-lowlatency-64kUbuntu

Fixed in:6.8.0-78.78.1~22.04.1USN-7703-1

Fixed in:6.8.0-78.78.1USN-7703-1

linux-image-6.8.1-1030-realtimeUbuntu

Fixed in:6.8.1-1030.31USN-7703-1

linux-image-awsUbuntu

Fixed in:6.8.0-1035.37~22.04.1USN-7703-2

linux-image-aws-6.8Ubuntu

Fixed in:6.8.0-1035.37~22.04.1USN-7703-2

Fixed in:6.8.0-1035.37USN-7703-1

linux-image-aws-64kUbuntu

Fixed in:6.8.0-1035.37~22.04.1USN-7703-2

linux-image-aws-64k-6.8Ubuntu

Fixed in:6.8.0-1035.37~22.04.1USN-7703-2

Fixed in:6.8.0-1035.37USN-7703-1

linux-image-aws-64k-lts-24.04Ubuntu

Fixed in:6.8.0-1035.37USN-7703-1

linux-image-aws-lts-24.04Ubuntu

Fixed in:6.8.0-1035.37USN-7703-1

linux-image-azureUbuntu

Fixed in:6.8.0-1034.39~22.04.1USN-7737-1

Fixed in:6.11.0-1015.15~24.04.1USN-7521-1

linux-image-azure-6.8Ubuntu

Fixed in:6.8.0-1034.39~22.04.1USN-7737-1

Fixed in:6.8.0-1034.39USN-7737-1

linux-image-azure-fdeUbuntu

Fixed in:6.8.0-1034.39~22.04.1USN-7737-1

Fixed in:6.11.0-1015.15~24.04.1USN-7521-1

linux-image-azure-fde-6.8Ubuntu

Fixed in:6.8.0-1034.39~22.04.1USN-7737-1

Fixed in:6.8.0-1034.39USN-7737-1

linux-image-azure-fde-lts-24.04Ubuntu

Fixed in:6.8.0-1034.39USN-7737-1

linux-image-azure-lts-24.04Ubuntu

Fixed in:6.8.0-1034.39USN-7737-1

linux-image-azure-nvidiaUbuntu

Fixed in:6.8.0-1022.23USN-7737-1

linux-image-azure-nvidia-6.8Ubuntu

Fixed in:6.8.0-1022.23USN-7737-1

linux-image-azure-nvidia-lts-24.04Ubuntu

Fixed in:6.8.0-1022.23USN-7737-1

linux-image-gcpUbuntu

Fixed in:6.8.0-1036.38~22.04.1USN-7703-2

Fixed in:6.11.0-1015.15~24.04.1USN-7521-1

linux-image-gcp-6.8Ubuntu

Fixed in:6.8.0-1036.38~22.04.1USN-7703-2

Fixed in:6.8.0-1036.38USN-7703-2

linux-image-gcp-64kUbuntu

Fixed in:6.8.0-1036.38~22.04.1USN-7703-2

Fixed in:6.11.0-1015.15~24.04.1USN-7521-1

linux-image-gcp-64k-6.8Ubuntu

Fixed in:6.8.0-1036.38~22.04.1USN-7703-2

Fixed in:6.8.0-1036.38USN-7703-2

linux-image-gcp-64k-lts-24.04Ubuntu

Fixed in:6.8.0-1036.38USN-7703-2

linux-image-gcp-lts-24.04Ubuntu

Fixed in:6.8.0-1036.38USN-7703-2

linux-image-genericUbuntu

Fixed in:6.8.0-78.78USN-7703-1

linux-image-generic-6.8Ubuntu

Fixed in:6.8.0-78.78~22.04.1USN-7703-4

Fixed in:6.8.0-78.78USN-7703-1

linux-image-generic-64kUbuntu

Fixed in:6.8.0-78.78USN-7703-1

linux-image-generic-64k-6.8Ubuntu

Fixed in:6.8.0-78.78~22.04.1USN-7703-4

Fixed in:6.8.0-78.78USN-7703-1

linux-image-generic-64k-hwe-22.04Ubuntu

Fixed in:6.8.0-78.78~22.04.1USN-7703-4

linux-image-generic-64k-hwe-24.04Ubuntu

Fixed in:6.11.0-26.26~24.04.1USN-7521-1

linux-image-generic-hwe-22.04Ubuntu

Fixed in:6.8.0-78.78~22.04.1USN-7703-4

linux-image-generic-hwe-24.04Ubuntu

Fixed in:6.11.0-26.26~24.04.1USN-7521-1

linux-image-generic-lpaeUbuntu

Fixed in:6.8.0-78.78USN-7703-1

linux-image-gkeUbuntu

Fixed in:6.8.0-1032.36USN-7703-4

linux-image-gke-6.8Ubuntu

Fixed in:6.8.0-1032.36USN-7703-4

linux-image-gkeopUbuntu

Fixed in:6.8.0-1019.21USN-7703-2

linux-image-gkeop-6.8Ubuntu

Fixed in:6.8.0-1019.21USN-7703-2

linux-image-ibmUbuntu

Fixed in:6.8.0-1033.33USN-7703-2

linux-image-ibm-6.8Ubuntu

Fixed in:6.8.0-1033.33~22.04.1USN-7703-2

Fixed in:6.8.0-1033.33USN-7703-2

linux-image-ibm-classicUbuntu

Fixed in:6.8.0-1033.33USN-7703-2

linux-image-ibm-lts-24.04Ubuntu

Fixed in:6.8.0-1033.33USN-7703-2

linux-image-kvmUbuntu

Fixed in:6.8.0-78.78USN-7703-1

linux-image-lowlatencyUbuntu

Fixed in:6.8.0-78.78.1USN-7703-1

linux-image-lowlatency-6.8Ubuntu

Fixed in:6.8.0-78.78.1~22.04.1USN-7703-1

Fixed in:6.8.0-78.78.1USN-7703-1

linux-image-lowlatency-64kUbuntu

Fixed in:6.8.0-78.78.1USN-7703-1

linux-image-lowlatency-64k-6.8Ubuntu

Fixed in:6.8.0-78.78.1~22.04.1USN-7703-1

Fixed in:6.8.0-78.78.1USN-7703-1

linux-image-lowlatency-64k-hwe-22.04Ubuntu

Fixed in:6.8.0-78.78.1~22.04.1USN-7703-1

linux-image-lowlatency-64k-hwe-24.04Ubuntu

Fixed in:6.11.0-1014.15~24.04.1USN-7521-3

linux-image-lowlatency-hwe-22.04Ubuntu

Fixed in:6.8.0-78.78.1~22.04.1USN-7703-1

linux-image-lowlatency-hwe-24.04Ubuntu

Fixed in:6.11.0-1014.15~24.04.1USN-7521-3

linux-image-nvidiaUbuntu

Fixed in:6.8.0-1035.38USN-7703-4

linux-image-nvidia-6.8Ubuntu

Fixed in:6.8.0-1035.38~22.04.1USN-7703-4

Fixed in:6.8.0-1035.38USN-7703-4

linux-image-nvidia-64kUbuntu

Fixed in:6.8.0-1035.38USN-7703-4

linux-image-nvidia-64k-6.8Ubuntu

Fixed in:6.8.0-1035.38~22.04.1USN-7703-4

Fixed in:6.8.0-1035.38USN-7703-4

linux-image-nvidia-64k-hwe-22.04Ubuntu

Fixed in:6.8.0-1035.38~22.04.1USN-7703-4

linux-image-nvidia-hwe-22.04Ubuntu

Fixed in:6.8.0-1035.38~22.04.1USN-7703-4

linux-image-nvidia-lowlatencyUbuntu

Fixed in:6.8.0-1035.38.1USN-7703-4

linux-image-nvidia-lowlatency-6.8Ubuntu

Fixed in:6.8.0-1035.38.1USN-7703-4

linux-image-nvidia-lowlatency-64kUbuntu

Fixed in:6.8.0-1035.38.1USN-7703-4

linux-image-nvidia-lowlatency-64k-6.8Ubuntu

Fixed in:6.8.0-1035.38.1USN-7703-4

linux-image-oem-22.04Ubuntu

Fixed in:6.8.0-78.78~22.04.1USN-7703-4

linux-image-oem-22.04aUbuntu

Fixed in:6.8.0-78.78~22.04.1USN-7703-4

linux-image-oem-22.04bUbuntu

Fixed in:6.8.0-78.78~22.04.1USN-7703-4

linux-image-oem-22.04cUbuntu

Fixed in:6.8.0-78.78~22.04.1USN-7703-4

linux-image-oem-22.04dUbuntu

Fixed in:6.8.0-78.78~22.04.1USN-7703-4

linux-image-oem-24.04bUbuntu

Fixed in:6.11.0-1022.22USN-7521-1

linux-image-oracleUbuntu

Fixed in:6.8.0-1032.33~22.04.1USN-7703-3

linux-image-oracle-6.8Ubuntu

Fixed in:6.8.0-1032.33~22.04.1USN-7703-3

Fixed in:6.8.0-1032.33USN-7703-3

linux-image-oracle-64kUbuntu

Fixed in:6.8.0-1032.33~22.04.1USN-7703-3

linux-image-oracle-64k-6.8Ubuntu

Fixed in:6.8.0-1032.33~22.04.1USN-7703-3

Fixed in:6.8.0-1032.33USN-7703-3

linux-image-oracle-64k-lts-24.04Ubuntu

Fixed in:6.8.0-1032.33USN-7703-3

linux-image-oracle-lts-24.04Ubuntu

Fixed in:6.8.0-1032.33USN-7703-3

linux-image-raspiUbuntu

Fixed in:6.8.0-1035.39USN-7703-4

linux-image-raspi-6.8Ubuntu

Fixed in:6.8.0-1035.39USN-7703-4

linux-image-raspi-realtimeUbuntu

Fixed in:6.8.0-2028.29USN-7719-1

linux-image-raspi-realtime-6.8Ubuntu

Fixed in:6.8.0-2028.29USN-7719-1

linux-image-realtimeUbuntu

Fixed in:6.8.1-1030.31USN-7703-1

linux-image-realtime-6.8.1Ubuntu

Fixed in:6.8.1-1030.31USN-7703-1

linux-image-virtualUbuntu

Fixed in:6.8.0-78.78USN-7703-1

linux-image-virtual-6.8Ubuntu

Fixed in:6.8.0-78.78~22.04.1USN-7703-4

Fixed in:6.8.0-78.78USN-7703-1

linux-image-virtual-hwe-22.04Ubuntu

Fixed in:6.8.0-78.78~22.04.1USN-7703-4

linux-image-virtual-hwe-24.04Ubuntu

Fixed in:6.11.0-26.26~24.04.1USN-7521-1

linux-lowlatencyUbuntu

Fixed in:6.8.0-78.78.1USN-7703-1

linux-lowlatency-hwe-6.11Ubuntu

Fixed in:6.11.0-1014.15~24.04.1USN-7521-3

linux-lowlatency-hwe-6.8Ubuntu

Fixed in:6.8.0-78.78.1~22.04.1USN-7703-1

linux-nvidiaUbuntu

Fixed in:6.8.0-1035.38USN-7703-4

linux-nvidia-6.8Ubuntu

Fixed in:6.8.0-1035.38~22.04.1USN-7703-4

linux-nvidia-lowlatencyUbuntu

Fixed in:6.8.0-1035.38.1USN-7703-4

linux-oem-6.11Ubuntu

Fixed in:6.11.0-1022.22USN-7521-1

linux-oracleUbuntu

Fixed in:6.8.0-1032.33USN-7703-3

linux-oracle-6.8Ubuntu

Fixed in:6.8.0-1032.33~22.04.1USN-7703-3

linux-raspiUbuntu

Fixed in:6.8.0-1035.39USN-7703-4

linux-raspi-realtimeUbuntu

Fixed in:6.8.0-2028.29USN-7719-1

linux-realtimeUbuntu

Fixed in:6.8.1-1030.31USN-7703-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

0.21%probability of exploitation in 30 days

11thpercentile

Low risk: more likely to be exploited than 11% of all known CVEs.

References

Patch4

Related Vulnerabilities

Other CWE-416 (Use After Free) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2019-0708	Critical	9.8	100%	KEV + Ransom	-
CVE-2021-31166	Critical	9.8	100%	KEV	Fix
CVE-2015-5119	Critical	9.8	99%	KEV	-
CVE-2010-3962	High	8.1	97%	KEV	-
CVE-2015-0313	Critical	9.8	96%	KEV	Fix
CVE-2017-9798	High	7.5	95%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-10-01.