CVE-2025-37818 | LoongArch: Return NULL from huge_pte_offset() for invalid PMD

In the Linux kernel, the following vulnerability has been resolved: LoongArch: Return NULL from huge_pte_offset() for invalid PMD LoongArch's huge_pte_offset() currently returns a pointer to a PMD slot even if the underlying entry points to invalid_pte_table (indicating no mapping). Callers like smaps_hugetlb_range() fetch this invalid entry value (the address of invalid_pte_table) via this pointer. The generic is_swap_pte() check then incorrectly identifies this address as a swap entry on LoongArch, because it satisfies the "!pte_present() && !pte_none()" conditions. This misinterpretation, combined with a coincidental match by is_migration_entry() on the address bits, leads to kernel crashes in pfn_swap_entry_to_page(). Fix this at the architecture level by modifying huge_pte_offset() to check the PMD entry's content using pmd_none() before returning. If the entry is invalid (i.e., it points to invalid_pte_table), return NULL instead of the pointer to the slot.

Published: 2025-05-08 Last update: 2025-11-12 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Conclusion & alert: CVE-2025-37818 is rated Low Risk (29.5/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.07%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-37818

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-04 0.02% 0.07% +0.05%
2 2025-05-08 0.02%

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-37818

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
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]

Weakness enumeration for CVE-2025-37818

OS Trackers for CVE-2025-37818

vendor priority summary link
debian unimportant CVE-2025-37818 unimportant priority: Debian including 2 source packages (linux, linux-6.1), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 6. https://security-tracker.debian.org/tracker/CVE-2025-37818
redhat medium https://access.redhat.com/security/cve/CVE-2025-37818
suse medium CVE-2025-37818 severity moderate: SUSE including 26 source package names (cluster-md-kmp-default, dlm-kmp-default, …), 258 product×package rows across 50 product lines (SLES-LTSS-TERADATA 15 SP2, SUSE Linux Enterprise High Availability Extension 15 SP7, … (50 product lines)): Known Not Affected 258. https://www.suse.com/security/cve/CVE-2025-37818/
ubuntu medium CVE-2025-37818 medium priority: Ubuntu including 150 source packages (linux, linux-allwinner-5.19, …), 1485 status rows across 10 suites (bionic, focal, jammy, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 1095, not-affected 225, released 86, ignored 79. https://ubuntu.com/security/CVE-2025-37818

Affected software / configurations for CVE-2025-37818

Vendor Product Version Raw CPE
linux linux_kernel >= 5.19, < 6.1.136 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.2, < 6.6.89 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.7, < 6.12.26 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.13, < 6.14.5 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel 6.15 cpe:2.3:o:linux:linux_kernel:6.15:rc1:*:*:*:*:*:*
linux linux_kernel 6.15 cpe:2.3:o:linux:linux_kernel:6.15:rc2:*:*:*:*:*:*
linux linux_kernel 6.15 cpe:2.3:o:linux:linux_kernel:6.15:rc3:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

References for CVE-2025-37818

cvelogic Threat Intelligence