CVE-2025-39845

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2025-09-22. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: None knownExposed: 0

A fix is available — apply it.

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

x86/mm/64: define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings()

Define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to ensure page tables are properly synchronized when calling p*d_populate_kernel().

For 5-level paging, synchronization is performed via pgd_populate_kernel(). In 4-level paging, pgd_populate() is a no-op, so synchronization is instead performed at the P4D level via p4d_populate_kernel().

This fixes intermittent boot failures on systems using 4-level paging and a large amount of persistent memory:

BUG: unable to handle page fault for address: ffffe70000000034 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI RIP: 0010:__init_single_page+0x9/0x6d Call Trace: __init_zone_device_page+0x17/0x5d memmap_init_zone_device+0x154/0x1bb pagemap_range+0x2e0/0x40f memremap_pages+0x10b/0x2f0 devm_memremap_pages+0x1e/0x60 dev_dax_probe+0xce/0x2ec [device_dax] dax_bus_probe+0x6d/0xc9 [... snip ...]

It also fixes a crash in vmemmap_set_pmd() caused by accessing vmemmap before sync_global_pgds() [1]:

BUG: unable to handle page fault for address: ffffeb3ff1200000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: Oops: 0002 [#1] PREEMPT SMP NOPTI Tainted: [W]=WARN RIP: 0010:vmemmap_set_pmd+0xff/0x230 vmemmap_populate_hugepages+0x176/0x180 vmemmap_populate+0x34/0x80 __populate_section_memmap+0x41/0x90 sparse_add_section+0x121/0x3e0 __add_pages+0xba/0x150 add_pages+0x1d/0x70 memremap_pages+0x3dc/0x810 devm_memremap_pages+0x1c/0x60 xe_devm_add+0x8b/0x100 [xe] xe_tile_init_noalloc+0x6a/0x70 [xe] xe_device_probe+0x48c/0x740 [xe] [... snip ...]

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity55% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
4%
KEV
Not listed

Published

September 19, 2025

Last Modified

July 14, 2026

Advisory Details (9)

Auto-updated Jul 16, 2026
Patch available.
generic

SSA-032379

https://cert-portal.siemens.com/productcert/html/ssa-032379.html
generic

SSA-019113

https://cert-portal.siemens.com/productcert/html/ssa-019113.html
generic Patch Available

[SECURITY] [DLA 4328-1] linux-6.1 security update

https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
generic

x86/mm/64: define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b7f4051dd3388edd30e9a6077c05c486aa31e0d4
generic

x86/mm/64: define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/744ff519c72de31344a627eaf9b24e9595aae554
generic

x86/mm/64: define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/6bf9473727569e8283c1e2445c7ac42cf4fc9fa9
generic

x86/mm/64: define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/6659d027998083fbb6d42a165b0c90dc2e8ba989
generic

x86/mm/64: define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/5f761d40ee95d2624f839c90ebeef2d5c55007f5
generic

x86/mm/64: define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/26ff568f390a531d1bd792e49f1a401849921960

Vendor Advisories for CVE-2025-39845(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(20)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-tools-raspi-nolpae (5.15.0.1091.89) @ jammy2026-05-21ubuntu
ubuntulinux-tools-azure-edge (5.15.0.1102.111~20.04.1) @ focal2026-05-21ubuntu
ubuntulinux-virtual-6.8 (6.8.0-106.106) @ noble2026-05-21ubuntu
ubuntulinux-tools-realtime-5.15 (5.15.0.1096.100) @ jammy2026-05-21ubuntu
ubuntulinux-xilinx-zynqmp-tools-5.15.0-1061 (5.15.0-1061.65) @ jammy2026-05-21ubuntu
ubuntulinux-tools-kvm-5.15 (5.15.0.1089.85) @ jammy2026-05-21ubuntu
ubuntulinux-tools-azure-fips-5.15 (5.15.0.1101.86) @ jammy2026-05-21ubuntu
ubuntulinux-tools-gcp-fips-5.15 (5.15.0.1097.87) @ jammy2026-05-21ubuntu
ubuntulinux-tools-gkeop-5.15 (5.15.0.1080.79) @ jammy2026-05-21ubuntu
ubuntulinux-tools-azure-lts-22.04 (5.15.0.1101.99) @ jammy2026-05-21ubuntu
ubuntulinux-tools-azure-fips-6.8 (6.8.0-1052.58+fips1) @ noble2026-05-21ubuntu
ubuntulinux-tools-raspi-realtime-6.8 (6.8.0-2040.41) @ noble2026-05-21ubuntu
ubuntulinux-tools-azure-edge (6.8.0-1051.57~22.04.1) @ jammy2026-05-21ubuntu
ubuntulinux-xilinx-zynqmp (6.8.0.1029.30) @ noble2026-05-21ubuntu
ubuntulinux-tools-nvidia-lowlatency-64k-6.8 (6.8.0-1049.52.1) @ noble2026-05-21ubuntu
ubuntulinux-tools-gcp-fips-6.8 (6.8.0-1052.55+fips1) @ noble2026-05-21ubuntu
ubuntulinux-tools-realtime-6.8.1 (6.8.1-1045.46) @ noble2026-05-21ubuntu
ubuntulinux-tools-aws-edge (6.8.0-1050.53~22.04.1) @ jammy2026-05-21ubuntu
ubuntulinux-tools-azure-lts-24.04 (6.8.0-1051.57) @ noble2026-05-21ubuntu
linuxKernel @ 5.15.192—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(19)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 9× in last 7d / 46× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 120 total refreshes for this CVE.

  1. 2026-07-26 14:54 UTCEPSS rescore
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  21. 2026-07-14 13:19 UTCNVD updateCVSS v3 → 5.5 · severity → MEDIUM
  22. 2026-07-14 13:11 UTCMITRE cvelistV5
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Related CVEs(same product + same vendor + same CWE)

Frequently asked(5)

What is CVE-2025-39845?
CVE-2025-39845 is a medium vulnerability published on September 19, 2025. In the Linux kernel, the following vulnerability has been resolved: x86/mm/64: define ARCHPAGETABLESYNCMASK and archsynckernel_mappings() Define ARCHPAGETABLESYNCMASK and archsynckernel_mappings() to ensure page tables are properly synchronized when calling p*dpopulatekernel(). For 5-level paging,…
When was CVE-2025-39845 disclosed?
CVE-2025-39845 was first published in the National Vulnerability Database on September 19, 2025, with the most recent update on July 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-39845 actively exploited?
CVE-2025-39845 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 96.2% of all scored CVEs.
What is the CVSS score of CVE-2025-39845?
CVE-2025-39845 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2025-39845?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-39845, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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