What is the CVSS score of CVE-2026-53370?

CVE-2026-53370 has a CVSS 3.1 base score of 5.5 (Medium). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 0.2%.

Is there a patch available for CVE-2026-53370?

Yes, a patch is available for CVE-2026-53370. Update the affected software to the latest version immediately.

Linux Kernel CVE-2026-53370

EUVD-2026-45440 MEDIUM

2026-07-19 Linux

GHSA-6xq9-44c7-g88v

Information Disclosure Linux Intel Red Hat Suse

5.5

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

5.5 MEDIUM

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

vuln.today AI

5.5 MEDIUM

Local access and low privilege required to invoke perf_event_open(); impact is availability-only via PMU misconfiguration with no confirmed confidentiality or integrity effects.

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

4.0 AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

SUSE

5.3 MEDIUM

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

Red Hat

5.5 LOW

qualitative

Primary rating from NVD.

CVSS VectorNVD

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

Analysis Generated

Jul 29, 2026 - 19:26 vuln.today

CVSS changed

Jul 29, 2026 - 17:07 NVD

5.5 (MEDIUM)

Patch available

Jul 19, 2026 - 11:02 EUVD

CVE Published

Jul 19, 2026 - 09:10 nvd

MEDIUM 5.5

CVE Published

Jul 19, 2026 - 09:10 cve.org

UNKNOWN (no severity yet)

DescriptionNVD

In the Linux kernel, the following vulnerability has been resolved:

perf/x86/intel: Improve validation and configuration of ACR masks

Currently there are several issues on the user space ACR mask validation and configuration.

The validation for user space ACR mask (attr.config2) is incomplete,

e.g., the ACR mask could include the index which belongs to another ACR events group, but it's not validated.

An early return on an invalid ACR mask caused all subsequent ACR groups

to be skipped.

The stale hardware ACR mask (hw.config1) is not cleared before setting

new hardware ACR mask.

The following changes address all of the above issues.

Figure out the event index group of an ACR group. Any bits in the

user-space mask not present in the index group are now dropped.

Instead of an early return on invalid bits, drop only the invalid

portions and continue iterating through all ACR events to ensure full configuration.

Explicitly clear the stale hardware ACR mask for each event prior to

writing the new configuration.

Besides, a non-leader event member of ACR group could be disabled in theory. This could cause bit-shifting errors in the acr_mask of remaining group members. But since ACR sampling requires all events to be active, this should not be a big concern in real use case. Add a "FIXME" comment to notice this risk.

AnalysisAI

Multiple ACR mask validation and configuration flaws in the Linux kernel's perf/x86/intel subsystem allow a local low-privileged user to trigger incorrect Intel PMU hardware counter configuration, resulting in high availability impact. Three distinct weaknesses exist: incomplete user-space ACR mask validation permitting cross-group index bits, an early-return logic error that silently skips all subsequent ACR group configuration, and failure to clear stale hardware ACR masks (hw.config1) before writing new values. No public exploit code is identified and EPSS sits at 0.17% (6th percentile), indicating negligible active exploitation probability; this is a maintenance-patch priority rather than an emergency.

Technical ContextAI

The vulnerability resides in the Linux kernel's Performance Monitoring Unit (PMU) driver for Intel x86 processors, specifically within the perf subsystem's handling of ACR (Advanced Counter Relocation) events. User-space configures ACR masks via attr.config2, which the kernel must validate and translate into hardware register values stored in hw.config1. The affected code path manages Intel-specific PMU hardware counter grouping, where ACR events must belong to the same index group. CPE cpe:2.3:a:linux:linux identifies the Linux kernel itself. No CWE is formally assigned, but the root causes map to improper input validation (analogous to CWE-20) for the cross-group mask bit issue and improper initialization (analogous to CWE-665) for the stale mask not being zeroed prior to reconfiguration. The combination produces bit-shifting errors in acr_mask computations for remaining group members when a non-leader event is disabled.

RemediationAI

Upgrade to Linux kernel 6.18.30, 7.0.7, or 7.1, which incorporate the upstream stable fixes available at https://git.kernel.org/stable/c/aab56b95bee3ff79176b13443cd9d7cfe9747df0, https://git.kernel.org/stable/c/5ad732a56be46aabf158c16aa0c095291727aaef, and https://git.kernel.org/stable/c/c05e01cef47d9b4969eae2dcf9467e2a555bcb4f. Ubuntu users should apply USN-8593-1 via standard package management. As a compensating control on systems where immediate patching is not feasible, set kernel.perf_event_paranoid to 2 or 3 via sysctl to restrict perf_event_open() to privileged users only - note this disables unprivileged performance monitoring for development and profiling workflows, which is a trade-off for environments relying on those capabilities. Systems not running on Intel hardware with ACR PMU support are not affected and require no action.

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