CVE-2026-23425 [High] | Security Vulnerability in Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Fix ID register initialization for non-protected pKVM guests In protected mode, the hypervisor maintains a separate instance of the `kvm` structure for each VM. For non-protected VMs, this structure is initialized from the host's `kvm` state. Currently, `pkvm_init_features_from_host()` copies the `KVM_ARCH_FLAG_ID_REGS_INITIALIZED` flag from the host without the underlying `id_regs` data being initialized. This results in the hypervisor seeing the flag as set while the ID registers remain zeroed. Consequently, `kvm_has_feat()` checks at EL2 fail (return 0) for non-protected VMs. This breaks logic that relies on feature detection, such as `ctxt_has_tcrx()` for TCR2_EL1 support. As a result, certain system registers (e.g., TCR2_EL1, PIR_EL1, POR_EL1) are not saved/restored during the world switch, which could lead to state corruption. Fix this by explicitly copying the ID registers from the host `kvm` to the hypervisor `kvm` for non-protected VMs during initialization, since we trust the host with its non-protected guests' features. Also ensure `KVM_ARCH_FLAG_ID_REGS_INITIALIZED` is cleared initially in `pkvm_init_features_from_host` so that `vm_copy_id_regs` can properly initialize them and set the flag once done.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.02%	0.12%	+0.10%
2	2026-04-04	—	0.02%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.02%

0.12%

+0.10%

2026-04-04

—

0.02%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
8.8	3.1	HIGH	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	2.0	6.0	416baaa9-dc9f-4396-8d5f-8c081fb06d67
5.5	3.1	MEDIUM	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	1.8	3.6	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

8.8

3.1

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H Click to expand

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L): A normal user session is enough; they don’t have to be admin.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

2.0

6.0

416baaa9-dc9f-4396-8d5f-8c081fb06d67

5.5

3.1

MEDIUM

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

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L): A normal user session is enough; they don’t have to be admin.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

1.8

3.6

[email protected]

OS Trackers for CVE-2026-23425

vendor	priority	summary	link
`debian`	unimportant	CVE-2026-23425 unimportant priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2026-23425
`redhat`	—	—	https://access.redhat.com/security/cve/CVE-2026-23425
`suse`	medium	CVE-2026-23425 severity moderate: SUSE including 25 source package names (cluster-md-kmp-default, dlm-kmp-default, …), 207 product×package rows across 37 product lines (SUSE Linux Enterprise High Availability Extension 15 SP7, SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS, … (37 product lines)): Known Not Affected 207.	https://www.suse.com/security/cve/CVE-2026-23425/
`ubuntu`	medium	CVE-2026-23425 medium priority: Ubuntu including 157 source packages (linux, linux-allwinner-5.19, …), 1413 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): DNE 1018, ignored 169, not-affected 122, released 83, needed 21.	https://ubuntu.com/security/CVE-2026-23425

Affected software / configurations for CVE-2026-23425

Vendor	Product	Version	Raw CPE
linux	linux_kernel	>= 6.14.1, < 6.18.17	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.19, < 6.19.7	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	6.14	cpe:2.3:o:linux:linux_kernel:6.14:-::::::
linux	linux_kernel	7.0	cpe:2.3:o:linux:linux_kernel:7.0:rc1::::::
linux	linux_kernel	7.0	cpe:2.3:o:linux:linux_kernel:7.0:rc2::::::
linux	linux_kernel	7.0	cpe:2.3:o:linux:linux_kernel:7.0:rc3::::::
linux	linux_kernel	7.0	cpe:2.3:o:linux:linux_kernel:7.0:rc4::::::
linux	linux_kernel	7.0	cpe:2.3:o:linux:linux_kernel:7.0:rc5::::::
linux	linux_kernel	7.0	cpe:2.3:o:linux:linux_kernel:7.0:rc6::::::
linux	linux_kernel	7.0	cpe:2.3:o:linux:linux_kernel:7.0:rc7::::::

References for CVE-2026-23425

URL	Tags
https://git.kernel.org/stable/c/7e7c2cf0024d89443a7af52e09e47b1fe634ab17	Patch
https://git.kernel.org/stable/c/858620655c1fbff05997e162fc7d83a3293d5142	Patch
https://git.kernel.org/stable/c/bce3847f7c51b86332bf2e554c9e80ca3820f16c	Patch

URL

CVE-2026-23425 | KVM: arm64: Fix ID register initialization for non-protected pKVM guests

Exploit prediction scoring system (EPSS) score for CVE-2026-23425

Common vulnerability scoring system (CVSS) metrics for CVE-2026-23425

Weakness enumeration for CVE-2026-23425

GitHub Security Advisory for CVE-2026-23425

OS Trackers for CVE-2026-23425

Affected software / configurations for CVE-2026-23425

References for CVE-2026-23425