VulnerabilityPublished 25 Jul 2025Updated 19 Nov 2025

CVE-2025-38447: Linux kernel · Out-of-bounds Read

Source GCVE Database

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Not known to be exploited · CVSS 7.1 High.

Data as of 13 Nov 2026, 20:33 UTC

CVSS 3.1 base score

7.1High

How severe the flaw is on the 0–10 CVSS scale.

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

Attack Vector: Local
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Jul 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-crvf-pv9v-3xvj

What to do

AI-suggested

A fix for this vulnerability has been implemented in the Linux kernel by refactoring the batched unmap logic into a safer helper function. Users and administrators should apply the official kernel updates that include this patch once available. Until patched, avoid running untrusted code that could trigger this condition.

Description

CVE-2025-38447 is a high-severity vulnerability in the Linux kernel's memory management subsystem. It involves a potential out-of-bounds access in the page table during batched unmap operations in the try_to_unmap_one() function. This flaw could be triggered from userspace, although the scenario is considered rare. The issue arises when a large folio's page table entries (PTEs) span multiple page tables, leading to reading beyond the valid PTE table boundary. The vulnerability has been addressed by refactoring the unmap logic into a new helper function that safely caps the batch size to avoid out-of-bounds access.

Impact

The vulnerability allows a local attacker with limited privileges (local vector, low complexity, no user interaction) to cause out-of-bounds memory reads in kernel space. The CVSS 3.1 score of 7.1 reflects high confidentiality impact and high availability impact, with no integrity impact. This could potentially lead to information disclosure or denial of service conditions. No known exploits in the wild have been reported.

Summary

The vulnerability CVE-2025-38447 affects the Linux kernel's reverse mapping (rmap) mechanism in the memory management (mm) subsystem. Specifically, the try_to_unmap_one() function's batched unmap logic could read past the end of a page table entry (PTE) table when handling large folios whose PTE mappings are not fully contained within a single page table. This out-of-bounds access is a memory safety issue categorized under CWE-125. The fix involves introducing a new helper function, folio_unmap_pte_batch(), which calculates a safe batch size by respecting both the virtual memory area (VMA) and page middle directory (PMD) boundaries, thus preventing invalid memory reads. The patch also simplifies the batching logic to support partial batches without special cases.

CWE-125Out-of-bounds Read (opens in a new tab)
Base weaknessCWE Top 25 (2025): #8
The product reads data past the end, or before the beginning, of the intended buffer.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Architecture and Design · Language Selection
Use a language that provides appropriate memory abstractions.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Overread Buffers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 13 Nov 2026, 20:33 UTC

WeaknessesCWE-125

Technical details

References

Community reviews

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