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NVD / CVE Program· CNA Linux

CVE-2025-40245: nios2: ensure that memblock.current_limit is set when setting pfn limits

Noroxi assessment

Priority: Monitor (action score 31/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.16% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 25f09699edd360b534ccae16bc276c3b52c471f3, 5c3e38a367822f036227dd52bac82dc4a05157e2, 8912814f14e298b83df072fecc1f7ed1b63b1b2c; azl3 kernel 6.6.112.1-2 on Azure Linux 3.0 6.6.117.1-1.

Low priority for now. Upgrade to Linux Linux 25f09699edd360b534ccae16bc276c3b52c471f3, 5c3e38a367822f036227dd52bac82dc4a05157e2, 8912814f14e298b83df072fecc1f7ed1b63b1b2c; azl3 kernel 6.6.112.1-2 on Azure Linux 3.0 6.6.117.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: nios2: ensure that memblock.current_limit is set when setting pfn limits On nios2, with CONFIG_FLATMEM set, the kernel relies on memblock_get_current_limit() to determine the limits of mem_map, in particular for max_low_pfn. Unfortunately, memblock.current_limit is only default initialized to MEMBLOCK_ALLOC_ANYWHERE at this point of the bootup, potentially leading to situations where max_low_pfn can erroneously exceed the value of max_pfn and, thus, the valid range of available DRAM. This can in turn cause kernel-level paging failures, e.g.: [ 76.900000] Unable to handle kernel paging request at virtual address 20303000 [ 76.900000] ea = c0080890, ra = c000462c, cause = 14 [ 76.900000] Kernel panic - not syncing: Oops [ 76.900000] ---[ end Kernel panic - not syncing: Oops ]--- This patch fixes this by pre-calculating memblock.current_limit based on the upper limits of the available memory ranges via adjust_lowmem_bounds, a simplified version of the equivalent implementation within the arm architecture.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Dec 4, 2025
Updated
Oct 19, 2026
EPSS
0.1% · 5th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CNA vs NVD score

NVD
—
CNA · Linux
7.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.12affected
    • 7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae and later · before 25f09699edd360b534ccae16bc276c3b52c471f3affected · git
    • 7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae and later · before 5c3e38a367822f036227dd52bac82dc4a05157e2affected · git
    • 7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae and later · before b1ec9faef7e36269ca3ec890972a78effbaeb975affected · git
    • 7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae and later · before 90f5f715550e07cd6a51f80fc3f062d832c8c997affected · git
    • 7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae and later · before 8912814f14e298b83df072fecc1f7ed1b63b1b2caffected · git
    • 7f7bc20bc41a4fbcd2db75b375ac95e5faf958ae and later · before a20b83cf45be2057f3d073506779e52c7fa17f94affected · git
    • before 5.12not affected · semver
    • 5.15.196 and later · up to and including 5.15.*not affected · semver
    • 6.1.158 and later · up to and including 6.1.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.158-16.1.158-1
Debian:13linuxbefore 6.12.57-16.12.57-1
Debian:14linuxbefore 6.17.6-16.17.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2025-40243Dec 4, 2025 · hfs: fix KMSAN uninit-value issue in hfs_find_set_zero_bits()
    31Monitor
  • ← EarlierCVE-2025-40244Dec 4, 2025 · hfsplus: fix KMSAN uninit-value issue in __hfsplus_ext_cache_extent()
    31Monitor
  • Later →CVE-2025-40246Dec 4, 2025 · xfs: fix out of bounds memory read error in symlink repair
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux25f09699edd360b534ccae16bc276c3b52c471f3Vendor (CNA)
Linux Linux5c3e38a367822f036227dd52bac82dc4a05157e2Vendor (CNA)
Linux Linux8912814f14e298b83df072fecc1f7ed1b63b1b2cVendor (CNA)
Linux Linux90f5f715550e07cd6a51f80fc3f062d832c8c997Vendor (CNA)
Linux Linuxa20b83cf45be2057f3d073506779e52c7fa17f94Vendor (CNA)
Linux Linuxb1ec9faef7e36269ca3ec890972a78effbaeb975Vendor (CNA)
azl3 kernel 6.6.112.1-2 on Azure Linux 3.06.6.117.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.158-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records