# CVE-2022-49085: drbd: Fix five use after free bugs in get\_initial\_state

- 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
- Published: 2025-02-26 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 4.5

## Description

In the Linux kernel, the following vulnerability has been resolved: drbd: Fix five use after free bugs in get_initial_state In get_initial_state, it calls notify_initial_state_done(skb,..) if cb->args[5]==1. If genlmsg_put() failed in notify_initial_state_done(), the skb will be freed by nlmsg_free(skb). Then get_initial_state will goto out and the freed skb will be used by return value skb->len, which is a uaf bug. What's worse, the same problem goes even further: skb can also be freed in the notify_*_state_change -> notify_*_state calls below. Thus 4 additional uaf bugs happened. My patch lets the problem callee functions: notify_initial_state_done and notify_*_state_change return an error code if errors happen. So that the error codes could be propagated and the uaf bugs can be avoid. v2 reports a compilation warning. This v3 fixed this warning and built successfully in my local environment with no additional warnings. v2: https://lore.kernel.org/patchwork/patch/1435218/

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
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## 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/0489700bfeb1e53eb2039c2291c67e71b0b40103
- https://git.kernel.org/stable/c/dcf6be17b5c53b741898d2223b23e66d682de300
- https://git.kernel.org/stable/c/188fe6b26765edbad4055611c0f788b6870f4024
- https://git.kernel.org/stable/c/b6a4055036eed1f5e239ce3d8b0db1ce38bba447
- https://git.kernel.org/stable/c/594205b4936771a250f9d141e7e0fff21c3dd2d9
- https://git.kernel.org/stable/c/a972c768723359ec995579902473028fe3cd64b1
- https://git.kernel.org/stable/c/de63e74da2333b4068bb79983e632db730fea97e
- https://git.kernel.org/stable/c/226e993c39405292781bfcf4b039a8db56aab362
- https://git.kernel.org/stable/c/aadb22ba2f656581b2f733deb3a467c48cc618f6

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