# CVE-2026-43088: net: af_key: zero aligned sockaddr tail in PF_KEY exports

> An attacker can read uninitialized kernel memory via PF_KEY exports, potentially exposing sensitive data.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:** 6 May 2026
- **Updated:** 14 Sep 2026
- **Also known as:** AZL-85895, BELL-CVE-2026-43088, DEBIAN-CVE-2026-43088, GHSA-5858-6g3v-6hmr, ROOT-OS-DEBIAN-11-CVE-2026-43088, ROOT-OS-DEBIAN-12-CVE-2026-43088, ROOT-OS-DEBIAN-13-CVE-2026-43088, ROOT-OS-UBUNTU-2204-CVE-2026-43088, ROOT-OS-UBUNTU-2404-CVE-2026-43088, UBUNTU-CVE-2026-43088

## What is CVE-2026-43088?

CVE-2026-43088 is a medium-severity vulnerability in Linux kernel, published on 6 May 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:

net: af_key: zero aligned sockaddr tail in PF_KEY exports

PF_KEY export paths use `pfkey_sockaddr_size()` when reserving sockaddr
payload space, so IPv6 addresses occupy 32 bytes on the wire. However,
`pfkey_sockaddr_fill()` initializes only the first 28 bytes of
`struct sockaddr_in6`, leaving the final 4 aligned bytes uninitialized.

Not every PF_KEY message is affected. The state and policy dump builders
already zero the whole message buffer before filling the sockaddr
payloads. Keep the fix to the export paths that still append aligned
sockaddr payloads with plain `skb_put()`:

  - `SADB_ACQUIRE`
  - `SADB_X_NAT_T_NEW_MAPPING`
  - `SADB_X_MIGRATE`

Fix those paths by clearing only the aligned sockaddr tail after
`pfkey_sockaddr_fill()`.

## Which versions are affected by CVE-2026-43088?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43088?

Apply the vendor's patch.

## Is CVE-2026-43088 being exploited?

There is no known exploitation of CVE-2026-43088 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-43088 and fix it if it is affected.

What it is: CVE-2026-43088 is a medium-severity vulnerability in Linux kernel, published on 6 May 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-2026-43088 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-43088/ (Markdown: https://insights.sbomify.com/CVE-2026-43088/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43088
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43088
- OSV: https://osv.dev/vulnerability/CVE-2026-43088

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43088/
Summaries are generated and may contain mistakes; the official description above is the record.