# CVE-2026-74630: ipv6: prevent in6_dev_get() from resurrecting inet6_dev

> A use-after-free in the Linux kernel IPv6 stack allows local attackers to execute code or escalate privileges via race conditions in device teardown.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** AZL-97059, BELL-CVE-2026-74630, DEBIAN-CVE-2026-74630, GHSA-6g8v-5hwp-cmr2, UBUNTU-CVE-2026-74630

## What is CVE-2026-74630?

CVE-2026-74630 is a high-severity use after free vulnerability in Linux, published on 22 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

ipv6: prevent in6_dev_get() from resurrecting inet6_dev

in6_dev_get() reads dev->ip6_ptr under RCU and then unconditionally
increments its refcount. Device teardown can clear the pointer and drop
the last reference between these operations. The increment then
resurrects an object whose RCU free has already been queued, so callers
can use it after it is freed.

Use refcount_inc_not_zero() and return NULL when the object has already
reached zero. RCU keeps the memory accessible through the attempted
reference acquisition, and a successful increment pins the object for
the caller.

An independent run on the exact unpatched 6f5156d7a31a (v7.2-rc3)
kernel reproduced the invalid reference acquisition as UID 1000:

  refcount_t: addition on 0; use-after-free.
  ip6_mc_source+0xef4/0x17e0

It was followed by the corresponding reference underflow in
ip6_mc_source(). The supplied trace from the same unpatched revision
additionally shows the access after the RCU read-side section ends:

  BUG: KASAN: slab-use-after-free in mutex_lock+0x76/0xe0
  Write of size 8 at addr ffff888015b50240 by task poc/1219

Bug found and triaged by OpenAI Security Research and
validated by Trail of Bits.

## Which versions are affected by CVE-2026-74630?


## How do I fix CVE-2026-74630?

Apply the vendor's patch.

## Is CVE-2026-74630 being exploited?

There is no known exploitation of CVE-2026-74630 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74630 and fix it if it is affected.

What it is: CVE-2026-74630 is a high-severity use after free vulnerability in Linux, published on 22 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-74630 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-74630/ (Markdown: https://insights.sbomify.com/CVE-2026-74630/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74630
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74630
- OSV: https://osv.dev/vulnerability/CVE-2026-74630

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74630/
Summaries are generated and may contain mistakes; the official description above is the record.