powerpc/pseries: Enforce hcall result buffer validity and size

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.

Timeline

Scores

EPSS (exploitation in 30 days)

0.30% · top 77% of all CVEs (12 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.

Affected products

• Linux · Linux

  • affected b9377ffc3a03cde558d76349a262a1adbb6d3112 – < acf2b80c31c37acab040baa3cf5f19fbd5140b18
  • affected b9377ffc3a03cde558d76349a262a1adbb6d3112 – < 19c166ee42cf16d8b156a6cb4544122d9a65d3ca
  • affected b9377ffc3a03cde558d76349a262a1adbb6d3112 – < a8c988d752b3d98d5cc1e3929c519a55ef55426c
  • affected b9377ffc3a03cde558d76349a262a1adbb6d3112 – < 262e942ff5a839b9e4f3302a8987928b0c8b8a2d
  • affected b9377ffc3a03cde558d76349a262a1adbb6d3112 – < 8aa11aa001576bf3b00dcb8559564ad7a3113588
  • affected b9377ffc3a03cde558d76349a262a1adbb6d3112 – < 3ad0034910a57aa88ed9976b1431b7b8c84e0048
  • affected b9377ffc3a03cde558d76349a262a1adbb6d3112 – < aa6107dcc4ce9a3451f2d729204713783b657257
  • affected b9377ffc3a03cde558d76349a262a1adbb6d3112 – < ff2e185cf73df480ec69675936c4ee75a445c3e4

• Linux · Linux

  • affected 2.6.19
  • unaffected < 2.6.19
  • unaffected 4.19.317 – ≤ 4.19.*
  • unaffected 5.4.279 – ≤ 5.4.*
  • unaffected 5.10.221 – ≤ 5.10.*
  • unaffected 5.15.162 – ≤ 5.15.*
  • unaffected 6.1.96 – ≤ 6.1.*
  • unaffected 6.6.36 – ≤ 6.6.*
  • unaffected 6.9.7 – ≤ 6.9.*
  • unaffected 6.10 – ≤ *

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2024-38771 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2024-40974](https://cveledger.app/badge/CVE-2024-40974.svg)](https://cveledger.app/cve/CVE-2024-40974)

Record last updated 5 Aug 2026, 11:34 UTC.