CVE-2024-40974

HIGH
Published Jul 12, 2024 Modified Nov 3, 2025 CWE-787

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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CVSS v3.1 Score

7.8
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-787 Out-of-bounds Write

Affected Products

Vendor Product
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel

References

Advisories & Patches

https://git.kernel.org/stable/c/19c166ee42cf16d8b156a6cb4544122d9a65d3ca https://git.kernel.org/stable/c/262e942ff5a839b9e4f3302a8987928b0c8b8a2d https://git.kernel.org/stable/c/3ad0034910a57aa88ed9976b1431b7b8c84e0048 https://git.kernel.org/stable/c/8aa11aa001576bf3b00dcb8559564ad7a3113588 https://git.kernel.org/stable/c/a8c988d752b3d98d5cc1e3929c519a55ef55426c https://git.kernel.org/stable/c/aa6107dcc4ce9a3451f2d729204713783b657257 https://git.kernel.org/stable/c/acf2b80c31c37acab040baa3cf5f19fbd5140b18 https://git.kernel.org/stable/c/ff2e185cf73df480ec69675936c4ee75a445c3e4 https://git.kernel.org/stable/c/19c166ee42cf16d8b156a6cb4544122d9a65d3ca https://git.kernel.org/stable/c/262e942ff5a839b9e4f3302a8987928b0c8b8a2d https://git.kernel.org/stable/c/3ad0034910a57aa88ed9976b1431b7b8c84e0048 https://git.kernel.org/stable/c/8aa11aa001576bf3b00dcb8559564ad7a3113588 https://git.kernel.org/stable/c/a8c988d752b3d98d5cc1e3929c519a55ef55426c https://git.kernel.org/stable/c/aa6107dcc4ce9a3451f2d729204713783b657257 https://git.kernel.org/stable/c/acf2b80c31c37acab040baa3cf5f19fbd5140b18 https://git.kernel.org/stable/c/ff2e185cf73df480ec69675936c4ee75a445c3e4

Frequently Asked Questions

What is CVE-2024-40974? +
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. It has a CVSS v3.1 base score of 7.8 (HIGH).
How severe is CVE-2024-40974? +
CVE-2024-40974 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.
What products are affected by CVE-2024-40974? +
CVE-2024-40974 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2024-40974? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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