CVE-2024-40974

Local kernel corruption via undersized hcall buffers

Published Jul 12, 2024 · Updated Aug 5, 2026

Out-of-bounds write in the Linux powerpc/pseries subsystem allows local users to corrupt kernel memory through hypercall result buffers. The plpar_hcall9 wrapper writes nine doublewords while affected callers can supply a four-doubleword on-stack buffer, overwriting 40 adjacent bytes. Exploitation requires an unprivileged account on a PPC64 pSeries guest and access to the affected read or ioctl path, enabling kernel-memory disclosure or modification and a kernel panic.

CVSS severity7.8
High
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in the Linux powerpc/pseries subsystem allows local users to corrupt kernel memory through hypercall result buffers. The plpar_hcall9 wrapper writes nine doublewords while affected callers can supply a four-doubleword on-stack buffer, overwriting 40 adjacent bytes. Exploitation requires an unprivileged account on a PPC64 pSeries guest and access to the affected read or ioctl path, enabling kernel-memory disclosure or modification and a kernel panic.

The record

CVE
CVE-2024-40974
Published
Jul 12, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 12, 2024CVE 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=2.6.19
  2. Affected versionversion=b9377ffc3a03cde558d76349a262a1adbb6d3112 <19c166ee42cf16d8b156a6cb4544122d9a65d3ca
  3. Affected versionversion=b9377ffc3a03cde558d76349a262a1adbb6d3112 <262e942ff5a839b9e4f3302a8987928b0c8b8a2d
  4. Affected versionversion=b9377ffc3a03cde558d76349a262a1adbb6d3112 <3ad0034910a57aa88ed9976b1431b7b8c84e0048
  5. Affected versionversion=b9377ffc3a03cde558d76349a262a1adbb6d3112 <8aa11aa001576bf3b00dcb8559564ad7a3113588
  6. Affected versionversion=b9377ffc3a03cde558d76349a262a1adbb6d3112 <a8c988d752b3d98d5cc1e3929c519a55ef55426c
  7. Affected versionversion=b9377ffc3a03cde558d76349a262a1adbb6d3112 <aa6107dcc4ce9a3451f2d729204713783b657257
  8. Affected versionversion=b9377ffc3a03cde558d76349a262a1adbb6d3112 <acf2b80c31c37acab040baa3cf5f19fbd5140b18
  9. Affected versionversion=b9377ffc3a03cde558d76349a262a1adbb6d3112 <ff2e185cf73df480ec69675936c4ee75a445c3e4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.19; version=b9377ffc3a03cde558d76349a262a1adbb6d3112 <19c166ee42cf16d8b156a6cb4544122d9a65d3ca; version=b9377ffc3a03cde558d76349a262a1adbb6d3112 <262e942ff5a839b9e4f3302a8987928b0c8b8a2d; version=b9377ffc3a03cde558d76349a262a1adbb6d3112 <3ad0034910a57aa88ed9976b1431b7b8c84e0048; version=b9377ffc3a03cde558d76349a262a1adbb6d3112 <8aa11aa001576bf3b00dcb8559564ad7a3113588; version=b9377ffc3a03cde558d76349a262a1adbb6d3112 <a8c988d752b3d98d5cc1e3929c519a55ef55426c; version=b9377ffc3a03cde558d76349a262a1adbb6d3112 <aa6107dcc4ce9a3451f2d729204713783b657257; version=b9377ffc3a03cde558d76349a262a1adbb6d3112 <acf2b80c31c37acab040baa3cf5f19fbd5140b18; version=b9377ffc3a03cde558d76349a262a1adbb6d3112 <ff2e185cf73df480ec69675936c4ee75a445c3e4

Published CVSS scores

7.8Linux kernel CNACVSS: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

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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

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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