CVE-2025-38257

Kernel data disclosure and crash via ioctl overflow

Published Jul 9, 2025 · Updated Aug 5, 2026

Integer overflow in the Linux s390 pkey ioctl allows local users to disclose kernel heap data or crash the system with a crafted APQN count. The _copy_apqns_from_user() path multiplies the user-controlled nr_apqns count before memdup_user(), allowing wraparound to allocate a buffer smaller than the count later traversed. Reachability requires an s390 system with CONFIG_PKEY and /dev/pkey access; an unprivileged local process can trigger an out-of-bounds read, kernel panic, or CPU stall.

CVSS severity7.3
High
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer overflow in the Linux s390 pkey ioctl allows local users to disclose kernel heap data or crash the system with a crafted APQN count. The _copy_apqns_from_user() path multiplies the user-controlled nr_apqns count before memdup_user(), allowing wraparound to allocate a buffer smaller than the count later traversed. Reachability requires an s390 system with CONFIG_PKEY and /dev/pkey access; an unprivileged local process can trigger an out-of-bounds read, kernel panic, or CPU stall.

The record

CVE
CVE-2025-38257
Published
Jul 9, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-190, T1106
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 9, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.4
  2. Affected versionversion=f2bbc96e7cfad3891b7bf9bd3e566b9b7ab4553d <73483ca7e07a5e39bdf612eec9d3d293e8bef649
  3. Affected versionversion=f2bbc96e7cfad3891b7bf9bd3e566b9b7ab4553d <7360ee47599af91a1d5f4e74d635d9408a54e489
  4. Affected versionversion=f2bbc96e7cfad3891b7bf9bd3e566b9b7ab4553d <88f3869649edbc4a13f6c2877091f81cd5a50f05
  5. Affected versionversion=f2bbc96e7cfad3891b7bf9bd3e566b9b7ab4553d <ad1bdd24a02d5a8d119af8e4cd50933780a6d29f
  6. Affected versionversion=f2bbc96e7cfad3891b7bf9bd3e566b9b7ab4553d <f855b119e62b004a5044ed565f2a2b368c4d3f16
  7. Affected versionversion=f2bbc96e7cfad3891b7bf9bd3e566b9b7ab4553d <faa1ab4a23c42e34dc000ef4977b751d94d5148c

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.4; version=f2bbc96e7cfad3891b7bf9bd3e566b9b7ab4553d <73483ca7e07a5e39bdf612eec9d3d293e8bef649; version=f2bbc96e7cfad3891b7bf9bd3e566b9b7ab4553d <7360ee47599af91a1d5f4e74d635d9408a54e489; version=f2bbc96e7cfad3891b7bf9bd3e566b9b7ab4553d <88f3869649edbc4a13f6c2877091f81cd5a50f05; version=f2bbc96e7cfad3891b7bf9bd3e566b9b7ab4553d <ad1bdd24a02d5a8d119af8e4cd50933780a6d29f; version=f2bbc96e7cfad3891b7bf9bd3e566b9b7ab4553d <f855b119e62b004a5044ed565f2a2b368c4d3f16; version=f2bbc96e7cfad3891b7bf9bd3e566b9b7ab4553d <faa1ab4a23c42e34dc000ef4977b751d94d5148c

Published CVSS scores

7.3Linux kernel CVE teamCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H
7.3UbuntuCVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
7.8UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound
T1106Native API

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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