# CVE-2025-40009: linux: In the Linux kernel, the following vulnerability has been resolved:  fs/proc/task_mmu: check p->vec_buf for NULL  Whe...

CVE-2025-40009 is fixed in 35 products on 1 platform, first by DEBIAN-CVE-2025-40009, released October 20, 2025. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2025-40009
- Priority: High
- CVSS: n/a (important)
- EPSS: 0.0024
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 20, 2025

## Description

In the Linux kernel, the following vulnerability has been resolved:  fs/proc/task_mmu: check p->vec_buf for NULL  When the PAGEMAP_SCAN ioctl is invoked with vec_len = 0 reaches pagemap_scan_backout_range(), kernel panics with null-ptr-deref:  [   44.936808] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI [   44.937797] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] [   44.938391] CPU: 1 UID: 0 PID: 2480 Comm: reproducer Not tainted 6.17.0-rc6 #22 PREEMPT(none) [   44.939062] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 [   44.939935] RIP: 0010:pagemap_scan_thp_entry.isra.0+0x741/0xa80  <snip registers, unreliable trace>  [   44.946828] Call Trace: [   44.947030]  <TASK> [   44.949219]  pagemap_scan_pmd_entry+0xec/0xfa0 [   44.952593]  walk_pmd_range.isra.0+0x302/0x910 [   44.954069]  walk_pud_range.isra.0+0x419/0x790 [   44.954427]  walk_p4d_range+0x41e/0x620 [   44.954743]  walk_pgd_range+0x31e/0x630 [   44.955057]  __walk_page_range+0x160/0x670 [   44.956883]  walk_page_range_mm+0x408/0x980 [   44.958677]  walk_page_range+0x66/0x90 [   44.958984]  do_pagemap_scan+0x28d/0x9c0 [   44.961833]  do_pagemap_cmd+0x59/0x80 [   44.962484]  __x64_sys_ioctl+0x18d/0x210 [   44.962804]  do_syscall_64+0x5b/0x290 [   44.963111]  entry_SYSCALL_64_after_hwframe+0x76/0x7e  vec_len = 0 in pagemap_scan_init_bounce_buffer() means no buffers are allocated and p->vec_buf remains set to NULL.  This breaks an assumption made later in pagemap_scan_backout_range(), that page_region is always allocated for p->vec_buf_index.  Fix it by explicitly checking p->vec_buf for NULL before dereferencing.  Other sites that might run into same deref-issue are already (directly or transitively) protected by checking p->vec_buf.  Note: From PAGEMAP_SCAN man page, it seems vec_len = 0 is valid when no output is requested and it's only the side effects caller is interested in, hence it passes check in pagemap_scan_get_args().  This issue was found by syzkaller.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | bpftool6.12 amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | bpftool6.12-debuginfo amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | dtb-aarch64 opensuse-leap 16.0 | 6.12.0-160000.7.1 | [OPENSUSE-SU-2025:20091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20091-1.md) | Nov 26, 2025 |
| Linux | kernel-64kb opensuse-leap 16.0 | 6.12.0-160000.7.1 | [OPENSUSE-SU-2025:20091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20091-1.md) | Nov 26, 2025 |
| Linux | kernel-64kb sles 16.0 | 6.12.0-160000.7.1 | [SUSE-SU-2025:21147-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21147-1.md) | Nov 26, 2025 |
| Linux | kernel-default opensuse-leap 16.0 | 6.12.0-160000.7.1 | [OPENSUSE-SU-2025:20091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20091-1.md) | Nov 26, 2025 |
| Linux | kernel-default sles 16.0 | 6.12.0-160000.7.1 | [SUSE-SU-2025:21147-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21147-1.md) | Nov 26, 2025 |
| Linux | kernel-default-base opensuse-leap 16.0 | 6.12.0-160000.6.1.160000.2.4 | [OPENSUSE-SU-2025:20091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20091-1.md) | Nov 26, 2025 |
| Linux | kernel-default-base sles 16.0 | 6.12.0-160000.6.1.160000.2.4 | [SUSE-SU-2025:21147-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21147-1.md) | Nov 26, 2025 |
| Linux | kernel-docs opensuse-leap 16.0 | 6.12.0-160000.7.1 | [OPENSUSE-SU-2025:20091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20091-1.md) | Nov 26, 2025 |
| Linux | kernel-docs sles 16.0 | 6.12.0-160000.7.1 | [SUSE-SU-2025:21147-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21147-1.md) | Nov 26, 2025 |
| Linux | kernel-kvmsmall opensuse-leap 16.0 | 6.12.0-160000.7.1 | [OPENSUSE-SU-2025:20091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20091-1.md) | Nov 26, 2025 |
| Linux | kernel-kvmsmall sles 16.0 | 6.12.0-160000.7.1 | [SUSE-SU-2025:21147-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21147-1.md) | Nov 26, 2025 |
| Linux | kernel-livepatch-6.12.53-69.119 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | kernel-obs-build opensuse-leap 16.0 | 6.12.0-160000.7.1 | [OPENSUSE-SU-2025:20091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20091-1.md) | Nov 26, 2025 |
| Linux | kernel-obs-qa opensuse-leap 16.0 | 6.12.0-160000.7.1 | [OPENSUSE-SU-2025:20091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20091-1.md) | Nov 26, 2025 |
| Linux | kernel-obs-qa sles 16.0 | 6.12.0-160000.7.1 | [SUSE-SU-2025:21147-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21147-1.md) | Nov 26, 2025 |
| Linux | kernel-rt opensuse-leap 16.0 | 6.12.0-160000.7.1 | [OPENSUSE-SU-2025:20091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20091-1.md) | Nov 26, 2025 |
| Linux | kernel-source opensuse-leap 16.0 | 6.12.0-160000.7.1 | [OPENSUSE-SU-2025:20091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20091-1.md) | Nov 26, 2025 |
| Linux | kernel-source sles 16.0 | 6.12.0-160000.7.1 | [SUSE-SU-2025:21147-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21147-1.md) | Nov 26, 2025 |
| Linux | kernel-syms opensuse-leap 16.0 | 6.12.0-160000.7.1 | [OPENSUSE-SU-2025:20091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20091-1.md) | Nov 26, 2025 |
| Linux | kernel-syms sles 16.0 | 6.12.0-160000.7.1 | [SUSE-SU-2025:21147-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21147-1.md) | Nov 26, 2025 |
| Linux | kernel-zfcpdump opensuse-leap 16.0 | 6.12.0-160000.7.1 | [OPENSUSE-SU-2025:20091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20091-1.md) | Nov 26, 2025 |
| Linux | kernel-zfcpdump sles 16.0 | 6.12.0-160000.7.1 | [SUSE-SU-2025:21147-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-21147-1.md) | Nov 26, 2025 |
| Linux | kernel6.12 amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | kernel6.12-debuginfo amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | kernel6.12-debuginfo-common-aarch64 amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | kernel6.12-debuginfo-common-x86_64 amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | kernel6.12-devel amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | kernel6.12-headers amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | kernel6.12-libbpf amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | kernel6.12-libbpf-debuginfo amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | kernel6.12-libbpf-devel amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | kernel6.12-libbpf-static amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | kernel6.12-modules-extra amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | kernel6.12-modules-extra-common amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | kernel6.12-tools amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | kernel6.12-tools-debuginfo amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | kernel6.12-tools-devel amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | linux Debian 13.5 (trixie) | 6.12.57-1 | [DEBIAN-CVE-2025-40009](https://patchblox.com/security/data/fix/linux/debian-cve-2025-40009.md) | Oct 20, 2025 |
| Linux | linux Debian 14 | 6.16.10-1 | [DEBIAN-CVE-2025-40009](https://patchblox.com/security/data/fix/linux/debian-cve-2025-40009.md) | Oct 20, 2025 |
| Linux | perf6.12 amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | perf6.12-debuginfo amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | python3-perf6.12 amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |
| Linux | python3-perf6.12-debuginfo amzn 2023 | 1:6.12.53-69.119.amzn2023 | [ALAS2023-2025-1254](https://patchblox.com/security/data/fix/linux/alas2023-2025-1254.md) | Oct 27, 2025 |

---

Data as of 2026-11-09T13:31:49Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.