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VulnerabilityPublished Updated

CVE-2024-40974: Linux kernel · powerpc/pseries: Enforce hcall result buffer validity and size

Source GCVE Database

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Not known to be exploited · CVSS 7.8 High.

Data as of 29 Oct 2026, 22:52 UTC

CVSS 3.1 base score
7.8High
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:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 12 Jul 2024

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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 29 Oct 2026.

Description

In the Linux kernel, the following vulnerability has been resolved: powerpc/pseries: Enforce hcall result buffer validity and size plpar_hcall(), plpar_hcall9(), and related functions expect callers to provide valid result buffers of certain minimum size. Currently this is communicated only through comments in the code and the compiler has no idea. For example, if I write a bug like this: long retbuf[PLPAR_HCALL_BUFSIZE]; // should be PLPAR_HCALL9_BUFSIZE plpar_hcall9(H_ALLOCATE_VAS_WINDOW, retbuf, ...); This compiles with no diagnostics emitted, but likely results in stack corruption at runtime when plpar_hcall9() stores results past the end of the array. (To be clear this is a contrived example and I have not found a real instance yet.) To make this class of error less likely, we can use explicitly-sized array parameters instead of pointers in the declarations for the hcall APIs. When compiled with -Warray-bounds[1], the code above now provokes a diagnostic like this: error: array argument is too small; is of size 32, callee requires at least 72 [-Werror,-Warray-bounds] 60 | plpar_hcall9(H_ALLOCATE_VAS_WINDOW, retbuf, | ^ ~~~~~~ [1] Enabled for LLVM builds but not GCC for now. See commit 0da6e5fd6c37 ("gcc: disable '-Warray-bounds' for gcc-13 too") and related changes.

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