# CVE-2024-46847: linux: In the Linux kernel, the following vulnerability has been resolved:  mm: vmalloc: ensure vmap_block is initialised be...

CVE-2024-46847 is fixed in linux on 1 platform, first by DEBIAN-CVE-2024-46847, released September 27, 2024. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2024-46847
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0023
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 27, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  mm: vmalloc: ensure vmap_block is initialised before adding to queue  Commit 8c61291fd850 ("mm: fix incorrect vbq reference in purge_fragmented_block") extended the 'vmap_block' structure to contain a 'cpu' field which is set at allocation time to the id of the initialising CPU.  When a new 'vmap_block' is being instantiated by new_vmap_block(), the partially initialised structure is added to the local 'vmap_block_queue' xarray before the 'cpu' field has been initialised.  If another CPU is concurrently walking the xarray (e.g.  via vm_unmap_aliases()), then it may perform an out-of-bounds access to the remote queue thanks to an uninitialised index.  This has been observed as UBSAN errors in Android:   | Internal error: UBSAN: array index out of bounds: 00000000f2005512 [#1] PREEMPT SMP  |  | Call trace:  |  purge_fragmented_block+0x204/0x21c  |  _vm_unmap_aliases+0x170/0x378  |  vm_unmap_aliases+0x1c/0x28  |  change_memory_common+0x1dc/0x26c  |  set_memory_ro+0x18/0x24  |  module_enable_ro+0x98/0x238  |  do_init_module+0x1b0/0x310  Move the initialisation of 'vb->cpu' in new_vmap_block() ahead of the addition to the xarray.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.10.11-1 | [DEBIAN-CVE-2024-46847](https://patchblox.com/security/data/fix/linux/debian-cve-2024-46847.md) | Sep 27, 2024 |
| Linux | linux Debian 14 | 6.10.11-1 | [DEBIAN-CVE-2024-46847](https://patchblox.com/security/data/fix/linux/debian-cve-2024-46847.md) | Sep 27, 2024 |

---

Data as of 2026-11-08T19:12:23Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo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.