CVE-2025-40019

Kernel memory corruption via unchecked ESSIV request length

Published Oct 24, 2025 · Updated Oct 24, 2025

Improper input validation in affected Linux kernel releases from 5.4 allows local users to corrupt memory via a malformed ESSIV AEAD request. The essiv_aead_crypt function rejected a negative associated-data-minus-IV length only for out-of-place encryption, while decryption and in-place requests passed it to scatterwalk_map_and_copy. Low-privileged local access and a malformed ESSIV request are required; the invalid copy writes outside its intended destination and allows a system crash or privilege escalation.

CVSS severity7.0
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in affected Linux kernel releases from 5.4 allows local users to corrupt memory via a malformed ESSIV AEAD request. The essiv_aead_crypt function rejected a negative associated-data-minus-IV length only for out-of-place encryption, while decryption and in-place requests passed it to scatterwalk_map_and_copy. Low-privileged local access and a malformed ESSIV request are required; the invalid copy writes outside its intended destination and allows a system crash or privilege escalation.

The record

CVE
CVE-2025-40019
Published
Oct 24, 2025
Updated
Oct 24, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 24, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 24, 2025Record 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=be1eb7f78aa8fbe34779c56c266ccd0364604e71 <248ff2797ff52a8cbf86507f9583437443bf7685
  3. Affected versionversion=be1eb7f78aa8fbe34779c56c266ccd0364604e71 <6bb73db6948c2de23e407fe1b7ef94bf02b7529f
  4. Affected versionversion=be1eb7f78aa8fbe34779c56c266ccd0364604e71 <da7afb01ba05577ba3629f7f4824205550644986
  5. Affected versionversion=be1eb7f78aa8fbe34779c56c266ccd0364604e71 <dc4c854a5e7453c465fa73b153eba4ef2a240abe
  6. Affected versionversion=be1eb7f78aa8fbe34779c56c266ccd0364604e71 <df58651968f82344a0ed2afdafd20ecfc55ff548
  7. Affected versionversion=be1eb7f78aa8fbe34779c56c266ccd0364604e71 <f37e7860dc5e94c70b4a3e38a5809181310ea9ac

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.4; version=be1eb7f78aa8fbe34779c56c266ccd0364604e71 <248ff2797ff52a8cbf86507f9583437443bf7685; version=be1eb7f78aa8fbe34779c56c266ccd0364604e71 <6bb73db6948c2de23e407fe1b7ef94bf02b7529f; version=be1eb7f78aa8fbe34779c56c266ccd0364604e71 <da7afb01ba05577ba3629f7f4824205550644986; version=be1eb7f78aa8fbe34779c56c266ccd0364604e71 <dc4c854a5e7453c465fa73b153eba4ef2a240abe; version=be1eb7f78aa8fbe34779c56c266ccd0364604e71 <df58651968f82344a0ed2afdafd20ecfc55ff548; version=be1eb7f78aa8fbe34779c56c266ccd0364604e71 <f37e7860dc5e94c70b4a3e38a5809181310ea9ac

Published CVSS scores

7.3SUSECVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
7.0SUSECVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
7.0OracleCVSS:3.1/AV:L/AC:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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