What is the CVSS score of CVE-2026-43344?

CVE-2026-43344 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: 0.0%.

Is there a patch available for CVE-2026-43344?

Yes, a patch is available for CVE-2026-43344. Update the affected software to the latest version immediately.

Linux Kernel CVE-2026-43344

EUVD-2026-28628 MEDIUM

Reachable Assertion (CWE-617)

2026-05-08 416baaa9-dc9f-4396-8d5f-8c081fb06d67

GHSA-m424-x6wr-wwgw

Intel Information Disclosure Linux 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

SUSE

MEDIUM

qualitative

Red Hat

5.5 LOW

qualitative

Primary rating from NVD.

CVSS VectorNVD

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

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

Analysis Generated

May 18, 2026 - 12:38 vuln.today

CVSS changed

May 18, 2026 - 12:37 NVD

5.5 (MEDIUM)

Patch available

May 08, 2026 - 15:17 EUVD

CVE Published

May 08, 2026 - 14:16 nvd

UNKNOWN (no severity yet)

DescriptionCVE.org

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

perf/x86/intel/uncore: Fix die ID init and look up bugs

In snbep_pci2phy_map_init(), in the nr_node_ids > 8 path, uncore_device_to_die() may return -1 when all CPUs associated with the UBOX device are offline.

Remove the WARN_ON_ONCE(die_id == -1) check for two reasons:

The current code breaks out of the loop. This is incorrect because

pci_get_device() does not guarantee iteration in domain or bus order, so additional UBOX devices may be skipped during the scan.

Returning -EINVAL is incorrect, since marking offline buses with

die_id == -1 is expected and should not be treated as an error.

Separately, when NUMA is disabled on a NUMA-capable platform, pcibus_to_node() returns NUMA_NO_NODE, causing uncore_device_to_die() to return -1 for all PCI devices. As a result, spr_update_device_location(), used on Intel SPR and EMR, ignores the corresponding PMON units and does not add them to the RB tree.

Fix this by using uncore_pcibus_to_dieid(), which retrieves topology from the UBOX GIDNIDMAP register and works regardless of whether NUMA is enabled in Linux. This requires snbep_pci2phy_map_init() to be added in spr_uncore_pci_init().

Keep uncore_device_to_die() only for the nr_node_ids > 8 case, where NUMA is expected to be enabled.

AnalysisAI

Die ID initialization and lookup bugs in the Linux kernel's Intel uncore performance monitoring subsystem (perf/x86/intel/uncore) can cause a reachable assertion trigger or silent loss of PMON unit visibility on Intel Sapphire Rapids (SPR) and Emerald Rapids (EMR) server hardware. Authenticated local users on affected systems may crash the kernel via the WARN_ON_ONCE reachable assertion (CWE-617) or, when NUMA is disabled on a NUMA-capable platform, cause all uncore PMON units to be silently dropped from the RB tree - rendering hardware performance monitoring inoperative. No public exploit exists and EPSS is 0.02%, indicating no active exploitation pressure at time of analysis.

Technical ContextAI

The vulnerability resides in the Linux kernel's x86 Intel uncore driver (drivers/perf/x86/intel/uncore), which manages Performance Monitoring Units (PMUs) on Intel server platforms. The root cause (CWE-617, Reachable Assertion) involves two related logic bugs: first, snbep_pci2phy_map_init() incorrectly breaks out of the PCI device scan loop when uncore_device_to_die() returns -1 (indicating offline CPUs), causing subsequent UBOX devices to be silently skipped since pci_get_device() does not guarantee domain/bus order; second, when Linux NUMA support is disabled on a NUMA-capable platform, pcibus_to_node() returns NUMA_NO_NODE, driving uncore_device_to_die() to return -1 for all PCI devices, which in turn causes spr_update_device_location() - used for SPR and EMR - to omit all corresponding PMON units from the RB tree used for topology-aware PMU enumeration. The fix replaces uncore_device_to_die() with uncore_pcibus_to_dieid() in the NUMA-disabled path, leveraging the UBOX GIDNIDMAP register for topology resolution independent of Linux NUMA state. Affected CPEs include cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* with specific rc releases through 7.0-rc7.

RemediationAI

Upstream fix commits are available at https://git.kernel.org/stable/c/6a5dc3ee97581da2907fc7acd62853f07184de67 (stable-6 tree, targeting the 6.19.14 patch release) and https://git.kernel.org/stable/c/a16d1ec4dd0cdcf689f324adde6067083bce9099 (mainline, targeting Linux 7.0). Administrators should update to Linux 6.19.14 or later in the stable series, or to Linux 7.0 once released, per vendor patch availability. Distribution-specific stable kernels (RHEL, SUSE, Ubuntu) should be monitored for backport availability. As an interim workaround on Intel SPR/EMR systems where NUMA is intentionally disabled, enabling NUMA in the kernel boot configuration (removing 'numa=off' or equivalent) will cause pcibus_to_node() to return valid node IDs, eliminating the -1 return path - however, this may alter memory allocation behavior and should be validated against workload requirements before deployment in production. No network-level mitigation is applicable given the local attack vector.

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